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In this study, we aimed to produce a standard, more functional, and nutritious yogurt by using 5 different combinations of cow milk and goat milk and 2 types of starter cultures (classical yogurt culture and commercial probiotic culture). It was determined that the use of different milk types and different starter cultures in yogurt production had a statistically very significant effect (P < 0.01) on all physicochemical, microbiological, and biochemical properties. In addition, the storage period was effective on all parameters examined at varying rates. In the context, the use of goat milk in the experimental yogurt samples caused an increase in the ACE inhibitory activity values and the count of S. thermophilus, while the use of cow milk caused an increase in serum separation and pH values. On the other hand, serum separation, pH values, and ACE inhibitory activity and phenylalanine and leucine levels were found to be higher in the yogurts produced by using ABT-2 probiotic culture. It was observed that an increase in the levels of asparagine, aspartic acid, proline, and serine, as well as lactic acid, orotic acid, and citric acid, is higher in the yogurts produced by using classical yogurt culture. It has been concluded that the combination of goat milk and cow milk at different proportions and the use of probiotic culture together in yogurt production can produce yogurt that is more functional and richer in terms of organic compounds and essential amino acids. [ABSTRACT FROM AUTHOR]

Protein–peptide-based materials typically possess high nutritional value and various physiological regulatory activities. This study evaluated the digestion, metabolism, and activity of Stropharia rugosoannulata protein–peptide-based materials. After the S. rugosoannulata protein–peptide-based materials were digested (simulated) orally, in the stomach, and in the intestines, the proportions of >10,000 Da, 5000~10,000 Da, and <180 Da in the digestion products increased, and the peptide content was maintained at more than 120 mg/g dry weight. The digestion products of eight test groups with different oral–gastrointestinal digestion-level settings all had suitable ACE inhibitory activity (IC50 range 0.004~0.096 mg/mL). The main metabolite groups were lipid-like molecules, fatty acids, carboxylic acids, their derivatives, amino acids, peptides, and analogs. Bile and glycosylated amino acids were the main compounds that caused differences between groups. KEGG pathways enriched in differentially expressed metabolites included eight significantly upregulated pathways, including valine, leucine, and isoleucine biosynthesis, etc., and six significantly downregulated pathways, including the citric acid cycle (tricarboxylic acid cycle), etc. The arginine and proline metabolism pathways and the aminoacyl-tRNA biosynthesis pathways were upregulation and downregulation pathways that enriched multiple differentially expressed metabolites. Twenty-six metabolites, including bile acids, total bile acids, and the essential amino acids L-isoleucine and L-leucine, were differentially expressed metabolite markers of the protein–peptide-based material oral–gastrointestinal digestion products. [ABSTRACT FROM AUTHOR]

In this paper, the active parts of sea cucumber (Apostichopus japonicus) with high antihypertensive activity were screened and the preparation process of active peptides was optimized. Different parts (body wall, intestine, and ovum) of A. japonicus were hydrolyzed by enzymolysis, and the ACE inhibition rate was used as an indicator to screen the optimal protease. The optimal active site for inhibition was selected by comparative screening of the half maximal inhibitory concentration (IC50) determination of ACE inhibitory rate of each lysate. Single factor and response surface tests were used to determine the optimum enzymatic hydrolysis conditions of the active peptides. The relative molecular weight of the protease hydrolysates was determined to determine its distribution range. The ACE inhibition activity of different components was analyzed after separation by ultrafiltration membrane. Search results, alkaline protease was selected as the optimal hydrolytic enzyme, and the IC50 values of ACE inhibition of each protease lysate from body wall, intestine and ovum were 1.11, 4.02, 0.65 mg/mL, respectively, so that A. japonicus ovum had a better ACE inhibition effect and were the optimal active site for inhibition. Its optimal preparation process parameters for enzymatic hydrolysis were as follows: 5 h enzymatic hydrolysis time, 3.5 U/mg enzyme added, 65.26 °C enzymatic hydrolysis temperature, 3.51% substrate concentration, pH9.02 enzymatic hydrolysis, and ACE inhibition rate of A. japonicusr ovum was 80.65%±0.52% under these conditions, which was close to the predicted value. The molecular weight of proteolytic products was concentrated under 3000 Da, accounting for 98.37% of the total content, of which 1000~3000 Da accounted for 9.50%, and less than 1000 Da accounted for 88.87%. The ACE inhibitory activity of oligopeptide components (IC50=0.30 mg/mL) isolated by ultrafiltration membrane was significantly higher than that of hydrolysates and trapped liquid components after process optimization. The results of this study would provide a theoretical basis for high-quality utilization of the by-products of A. japonicus, which could be used as high-quality resources for the isolation and purification of antihypertensive peptides.

In this study, the effect of the use of S. platensis, which is presented as an eco-friendly and alternative protein source, in the production of kefir, a probiotic dairy product, on various physicochemical properties as well as FAA, ACE inhibitory activity, proteolysis, TPC, DPPH, ABTS+, and mineral values was investigated. It was observed that the addition of S. platensis at different ratios to the kefir samples had a statistically very significant (p < 0.01) effect on all physicochemical analyses; L. mesenteroides count; all amino acids except isoleucine, aspartic acid, and glutamic acid; ACE inhibitory activity, TN, TCAN, TCAN/TN, mM Gly, TPC, DPPH, ABTS+, Na, Mg, K, and Fe. In plain kefir samples, mineral contents were determined by order of K > P > Na > Ca > Mg > Zn >> Fe > Cr > Cr > Mn. Furthermore, a general increase was observed in FAA, ACE inhibitory activity, TPC, DPPH, ABTS+, and mineral values, as well as in the counts of Lactococcus spp. and L. mesenteroides in the samples, depending on the proportion of S. platensis added, compared to plain kefir samples. In this context, it was concluded that the addition of S. platensis to kefir at different rates could meet various components required by the body on a daily basis and result in a nutraceutical product. [ABSTRACT FROM AUTHOR]

Copyright of Science & Technology of Food Industry is the property of Science & Technology of Food Industry Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Herein, the angiotensin I-converting enzyme (ACE) inhibitory activity, antioxidant capacity, total polyphenol contents (TPC), and phytochemical profiles of polar and non-polar extracts of dried Ziziphus jujuba fruits were investigated, along with the statistical determination of the main components responsible for ACE inhibitory activity. The non-polar extract expressed the strongest ACE inhibitory activity (99.81%) among the extracts. The non-polar extract also exhibited the highest DPPH scavenging activity (IC50 of 30.63), linoleic acid/β-carotene bleaching capacity (89.31%), and TPC (59.47 mg GAE/g). The phenolic profiles of the extracts were identified by LC-MS/MS, and the presence of seven triterpenoid species in the extracts was examined using GC-MS techniques. The principal constituents included 19 phenolics, 2 organic acids, and 4 triterpenoids. A Pearson correlation and principal component analysis were conducted to find the correlation between individual phenolic compounds and ACE inhibitory activity. [ABSTRACT FROM AUTHOR]

This study investigates the impact of elicitation on the phytochemical content, antioxidant activity, protein profiles, GABA content, and inhibitory activities against Angiotensin converting enzyme and alpha-amylase of two genotypes of Lab Lab sprouts, GUJ.W.2 and GNIB-22. Elicitation treatments with different substances triggered significant alterations in the sprouts' metabolic profile, enhancing their potential health benefits. Notably, there were evident changes in phenolic, ascorbic acid, flavonoid, and protein content across different elicited sprouts. Antioxidant activities were examined via DPPH and FRAP assays, GUJ.W.2 variety elicited, and control displayed (~ 30% inhibitory activity) higher antioxidant activity compared to GNIB-22. The GUJ.W.2 samples treated with glutamic acid and GNIB chitosan with lactic acid depicted statistical similarity in FRAP activity. Meanwhile, protein profiling, carried out through SDS-PAGE, suggested intrinsic genetic differences in protein synthesis mechanisms and metabolic activities between the genotypes. Furthermore, the elicited sprouts demonstrated high GABA content, a neuroactive amino acid with multiple physiological properties, including antihypertensive and antidiabetic effects. Remarkably, the elicited sprouts also exhibited enhanced ACE inhibitory activity (~ 80%), indicating potential hypertension management properties. Contrarily, the control group sprouts of GNIB- 22 showed higher alpha amylase inhibitory activity (~ 64%), denoting potential antidiabetic effects. The study demonstrates that the elicitation of Lab Lab seeds significantly enhances the nutritional and health-promoting properties of the sprouts. These findings pave the way for further exploration and potential application of Lab Lab sprouts in functional foods and therapeutic strategies. [ABSTRACT FROM AUTHOR]

Optimization of antioxidants and angiotensin-converting enzyme (ACE) inhibitory potential gelatin hydrolysate production from Labeo rohita (rohu) swim bladder (SBGH) by alcalase using central composite design (CCD) of response surface methodology (RSM) was investigated. The maximum degree of hydrolysis (DH), 2,2-diphenyl-1-picrylhydrazyl (DPPH), 2,2′-azino-bis-3-ethylbenzthiazoline-6-sulphonic acid (ABTS), total antioxidants (TAO), and ACE inhibitory activity were achieved at 0.1:1.0 (w/w) enzyme to substrate ratio, 61 °C hydrolysis temperature, and 94-min hydrolysis time. The resulting SBGH obtained at 19.92% DH exhibited the DPPH (24.28 µM TE/mg protein), ABTS (34.47 µM TE/mg protein), TAO (12.01 µg AAE/mg protein), and ACE inhibitory (4.91 µg/mg protein) activity. Furthermore, SBGH at 100 µg/ml displayed osteogenic property without any toxic effects on MC3T3-E1 cells. Besides, the protein content of rohu swim bladder gelatin (SBG) and SBGH was 93.68% and 94.98%, respectively. Both SBG and SBGH were rich in glycine, proline, glutamic acid, alanine, arginine, and hydroxyproline amino acids. Therefore, SBGH could be an effective nutraceutical in functional food development. [ABSTRACT FROM AUTHOR]

Consuming pomegranate juice (PJ) is beneficial for hypertensive regulation because of the phenolic compounds in PJ and their inhibitory activity on angiotensin-I-converting enzyme (ACE). To better utilize bioactive function of food, microorganism fermentation has been adopted to alter phenolic metabolism. This study confirms that even under in vitro digestion, fermented PJ (FPJ) maintains higher ACE inhibitory activity than that of PJ. The main phenolic compounds in PJ were compared either under fermentation or in vitro digestion. This study finds that fermentation promotes antioxidant capacity of PJ. The chemical properties of FPJ are evaluated and the corresponding relationship with bioactivities is analyzed. A sensory evaluation comparison is conducted between FPJ and PJ, furnishing interesting information for consumers. This study highlights the relationship between ACE inhibitory activity of PJ and phenolic composition under fermentation and in vitro digestion, providing novel insights for diet regulation of phenolic-rich FPJ in ACE inhibition therapy. [ABSTRACT FROM AUTHOR]

This study aimed to produce bioactive hydrolysates and peptide fractions from wheat gluten using Withania coagulans plant protease, and evaluate antioxidant and angiotensin-converting-enzyme inhibitory activities. Plant samples were collected and protease was extracted and purified using precipitation with ammonium sulfate. The enzyme activity was measured (7.3 U/ml) and highest enzyme activity (82%) was observed at 45 °C and pH 5. Wheat gluten hydrolysis was performed for 6 h and the degree of hydrolysis was measured (6.51%). Fractionation of gluten hydrolysates was performed using ultrafiltration and four peptide fractions were obtained, F1 (MW < 3 kDa), F2 (3 < MW < 30 kDa) and F3 (30 < MW < 100 kDa) and F4 (MW > 100 kDa). The highest solubility at pH 4 was exhibited by the F4 fraction. The highest DPPH radical scavenging activity was demonstrated by the F1 fraction. The highest value for angiotensin-converting-enzyme inhibitory activity was obtained for the F2 fraction. Our results showed that wheat gluten hydrolysis with Withania coagulans protease was an effective approach in order to generate bioactive hydrolysates and peptides, which could then be added to functional foods formulations and pharmaceutical products. [ABSTRACT FROM AUTHOR]

Protein hydrolysates from sea cucumber (Apostichopus japonicus) gonads are rich in active materials with remarkable angiotensin-converting enzyme (ACE) inhibitory activity. Alcalase was used to hydrolyze sea cucumber gonads, and the hydrolysate was separated by the ultrafiltration membrane to produce a low-molecular-weight peptide component (less than 3 kDa) with good ACE inhibitory activity. The peptide component (less than 3 kDa) was isolated and purified using a combination method of ACE gel affinity chromatography and reverse high-performance liquid chromatography. The purified fractions were identified by liquid chromatography–tandem mass spectrometry (LC–MS/MS), and the resulting products were filtered using structure-based virtual screening (SBVS) to obtain 20 peptides. Of those, three noncompetitive inhibitory peptides (DDQIHIF with an IC50 value of 333.5 μmol·L−1, HDWWKER with an IC50 value of 583.6 μmol·L−1, and THDWWKER with an IC50 value of 1291.8 μmol·L−1) were further investigated based on their favorable pharmacochemical properties and ACE inhibitory activity. Molecular docking studies indicated that the three peptides were entirely enclosed within the ACE protein cavity, improving the overall stability of the complex through interaction forces with the ACE active site. The total free binding energies (ΔGtotal) for DDQIHIF, HDWWKER, and THDWWKER were −21.9 Kcal·mol−1, −71.6 Kcal·mol−1, and −69.1 Kcal·mol−1, respectively. Furthermore, a short-term assay of antihypertensive activity in spontaneously hypertensive rats (SHRs) revealed that HDWWKER could significantly decrease the systolic blood pressure (SBP) of SHRs after intravenous administration. The results showed that based on the better antihypertensive activity of the peptide in SHRs, the feasibility of targeted affinity purification and computer-aided drug discovery (CADD) for the efficient screening and preparation of ACE inhibitory peptide was verified, which provided a new idea of modern drug development method for clinical use. [ABSTRACT FROM AUTHOR]

Protein–peptide-based materials typically possess high nutritional value and various physiological regulatory activities. This study evaluated the digestion, metabolism, and activity of Stropharia rugosoannulata protein–peptide-based materials. After the S. rugosoannulata protein–peptide-based materials were digested (simulated) orally, in the stomach, and in the intestines, the proportions of >10,000 Da, 5000~10,000 Da, and 50 range 0.004~0.096 mg/mL). The main metabolite groups were lipid-like molecules, fatty acids, carboxylic acids, their derivatives, amino acids, peptides, and analogs. Bile and glycosylated amino acids were the main compounds that caused differences between groups. KEGG pathways enriched in differentially expressed metabolites included eight significantly upregulated pathways, including valine, leucine, and isoleucine biosynthesis, etc., and six significantly downregulated pathways, including the citric acid cycle (tricarboxylic acid cycle), etc. The arginine and proline metabolism pathways and the aminoacyl-tRNA biosynthesis pathways were upregulation and downregulation pathways that enriched multiple differentially expressed metabolites. Twenty-six metabolites, including bile acids, total bile acids, and the essential amino acids L-isoleucine and L-leucine, were differentially expressed metabolite markers of the protein–peptide-based material oral–gastrointestinal digestion products.

Millet protein was used as raw material to prepare food-derived peptides with antioxidant activity and angiotensin transferase (ACE) inhibitory activity. Alkaline protease, neutral protease and flavor protease were used to hydrolyze millet protein. Three components with molecular weight < 3, 3-10 ku and > 10 ku were obtained from the hy-drolysate obtained by alkaline protease for 4 h, and their antioxidant and ACE inhibitory activities were determined. The results showed that the polypeptides with molecular weight < 3 ku obtained from the hydrolysate obtained by alkaline protease for 4 h after ultrafiltration had the highest antioxidant activity and ACE inhibitory activity, with DPPH scavenging capacity of 38.44%, ABTS free radical scavenging capacity of 81.62%, hydroxyl radical scavenging capacity of 68.49%. The inhibitory activity of ACE was 87.53%. The polypeptides obtained by this method have low molecular weight, high content of functional amino acids, and have good antioxidant and ACE inhibitory activities, which provide a basic for the development of antioxidant peptides and ACE inhibitory peptides, and provide a theoretical basis for the future industrial development. [ABSTRACT FROM AUTHOR]

旨在研究原料压榨制油的预处理方式对核桃多肽性质的影响。对核桃仁分别进行未预处理、去衣、焙烤预处理后，进行压榨提油，以提油后的饼为原料，经正己烷脱脂，碱性蛋白酶酶解制备核桃多肽，测定核桃多肽的功能特性和ACE抑制活性。结果表明：与未预处理、焙烤预处理比较，去衣预处理的核桃多肽的持水性(50 ℃，5.11 g/g)、吸油性(50 ℃，3.25 g/g)、乳化性(pH 9.0,6257%)、乳化稳定性(pH 9.0,84.51%)、起泡性(pH 9.0,117.49%)及ACE抑制率（63.04%）最高。综上，以去衣预处理压榨制油后的核桃饼为原料制备的核桃多肽具有良好的功能特性和ACE抑制活性。The aim was to study the effect of pretreatment methods of raw material pressing for oil on the properties of walnut polypeptide. The walnut kernels were untreated, peeled and roasted respectively,then pressed to extract oil.The cake after oil extraction was defatted by n-hexane and hydrolyzed by alkaline protease to produce walnut polypeptide, and the functional properties and ACE inhibitory activity of walnut polypeptide were determined. The results showed that compared with no treatment and roasting pretreatment, walnut polypeptide obtained by peeling of raw material had the highest water holding capacity (50 ℃, 5.11 g/g), oil absorption (50 ℃,3.25 g/g), emulsifying ability (pH 9.0, 62.57%), emulsifying stability (pH 9.0, 84.51%), foaming ability (pH 9.0, 117.49%) and ACE inhibitory rate( 63.04%). In conclusion, the walnut polypeptide prepared from walnut cake after peeling and pressing for oil production had good functional properties and ACE inhibitory activity.

This study aimed to investigate the effect of commercial protease enzymolysis and in vitro simulated gastrointestinal digestion on the release of ACE inhibitory peptides from the defatted goat milk powder with high digestibility, and to evaluate the necessity and the extent of enzymatic hydrolysis. Neutrase, alcalase, protamex, and flavourzyme were used for the enzymolysis of the defatted Kuishan goat milk powder. The goat milk and its enzymatic hydrolysates were further digested via simulated gastrointestinal digestion in vitro. The peptide content, ACE inhibitory activity and molecular weight distribution of the enzymatic hydrolysates and the simulated gastrointestinal digests were determined. Results showed that after the simulated gastrointestinal digestion in vitro, the peptide content and ACE inhibitory activity of the goat milk powder digests were 20.81 mg/mL and 62.55%, respectively. However, after moderate enzymatic hydrolysis by alcalase and flavourzyme, the peptide content and ACE inhibitory activity of simulated gastrointestinal digests decreased. After moderate enzymolysis by protamex, the peptide content and ACE inhibitory activity of simulated gastrointestinal digests were increased slightly to 22.67 mg/mL and 69.29%, respectively. After moderate enzymolysis by neutrase, the peptide content and ACE inhibitory activity of simulated gastrointestinal digests were significantly increased to 23.76 mg/mL and 81.10%, respectively. The molecular weight (MW) distribution results showed that after in vitro simulated gastrointestinal digestion, the amount of the small molecular peptides with MW

By devising a novel near-infrared (NIR) in-situ online monitoring system, this study proposed a new process control method for rice protein (RP) enzymatic hydrolysis in order to address the challenge of monitoring certain chemical indices in real-time. The endpoint of the enzymatic hydrolysis reaction and the flexible switching point of dual-enzyme hydrolysis were determined through real-time spectrum collection. Correction and prediction models were constructed to predict the angiotensin I-converting enzyme (ACE) inhibitory activity of RP hydrolysis as well as the endpoint and the dual-enzyme flexible switching point at different substrate concentrations in an attempt to establish the new control system. At the RP substrate concentrations of 35, 40, and 45 g/L, the R2 of predicted and measured ACE inhibitory activity values under hydrolysis with a single alcalase were 0.8852, 0.8360, and 0.8613, respectively. In addition, the ACE inhibitory activity of dual-enzyme hydrolysis showed a high growth trend before and after the flexible switching point, and the hydrolysis time was significantly shortened at the same endpoint threshold as that of single alcalase hydrolysis. The results indicated that this method is capable of accurately determining and regulating the endpoint and adaptable transition point of RP hydrolysis. Consequently, this approach holds promise for the regulation of food basic materials during large-scale processing operations.

Stirred-type fruit yoghurts with two different fruit purees (kiwifruit and banana) were produced and were investigated the physicochemical, volatile compounds, 2,2-diphenylpicrylhydrazyl (DPPH) free radical scavenging activity, cupric ion reducing capability (CUPRAC), total phenolic compounds (TPC), angiotensin-converting enzyme (ACE) inhibitory activity, 5-hydroxymethylfurfural (HMF) content, reducing sugar content and microstructure. The addition of fruit puree affected (p<0.01) total solids, fat, protein, ash, L*, a*, b*, volatile compounds, DPPH, CUPRAC, TPC, ACE inhibitory activity, HMF content, reducing sugar content and overall acceptability whereas it had an insignificant effect on the pH, titratable acidity, apparent viscosity, syneresis (p>0.05). Storage period significantly (p<0.01) affected the titratable acidity, DPPH, CUPRAC, TPC, ACE inhibitory activity, HMF content, reducing sugar content and overall acceptability, as well as the pH, apparent viscosity and a* (p<0.05). Although the addition of banana and kiwi relatively suppressed the characteristic flavour of the experimental yoghurt samples, it improved the DPPH, CUPRAC and TPC. On the other hand, the addition of banana-kiwi was found to increase the content of HMF, the toxic compound. Yoghurt can be recommended as an important source of bioactive compounds with ACE inhibitory activity. According to the microstructure analysis results, a more homogeneous structure was observed in the control group samples compared to the fruit-added yoghurt samples and it was determined that the serum pore diameters were smaller. [ABSTRACT FROM AUTHOR]

Copyright of Journal of Chinese Institute of Food Science & Technology is the property of Journal of Chinese Institute of Food Science & Technology Periodical Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Milk protein hydrolysate was optimally prepared by Protamex and PaproA (MP‐PP) exhibiting excellent angiotensin I‐converting enzyme (ACE) inhibitory activity (89.6%) at 0.5 mg/mL and protein recovery rate (79.0%). Meanwhile, MP‐PP was stable for acid–base and heat treatments, and even presented 80.5% of ACE inhibitory activity after handling in gastrointestinal fluids. However, transepithelial transportation via Caco‐2 cell monolayer lowered ACE inhibition of MP‐PP. Following the fractionation of MP‐PP, IESPPEI was identified as an outstanding ACE inhibitory peptide (IC50 of 6.4 μM), comparable with commercial VPP and IPP. Overall, MP‐PP and IESPPEI are potential functional ingredients to develop antihypertensive products. [ABSTRACT FROM AUTHOR]

Copyright of Journal of Chinese Institute of Food Science & Technology is the property of Journal of Chinese Institute of Food Science & Technology Periodical Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Abstract Sea cucumber is a precious and nutritious food with abundant protein and other bioactive compounds, among which sea cucumber peptide (SCP) exhibits many beneficial functions. Although research on the development of SCP is attracting more attention, the ability to translate these new findings into industrial practice and new products remains immature. This review summarizes the production and characterization of SCP and emphasizes recent advances in its bioactive properties, including antioxidative, angiotensin‐I converting enzyme‐inhibitory, immunomodulatory, anticancer, antifatigue, and neuroprotective effects. Meanwhile, the challenges and prospects of SCP development have been discussed in both scientific research and commercialization. SCP shows great potential in health promotion, yet several challenges need to be solved: the validation of health claims, clarification of its mechanisms, innovations to boost its bioavailability, and improvement of industrial production and sensory properties of end‐products. Hopefully, this information will provide a comprehensive perspective on developing SCP nutraceuticals and functional foods.

Protein hydrolysates from sea cucumber (Apostichopus japonicus) gonads are rich in active materials with remarkable angiotensin-converting enzyme (ACE) inhibitory activity. Alcalase was used to hydrolyze sea cucumber gonads, and the hydrolysate was separated by the ultrafiltration membrane to produce a low-molecular-weight peptide component (less than 3 kDa) with good ACE inhibitory activity. The peptide component (less than 3 kDa) was isolated and purified using a combination method of ACE gel affinity chromatography and reverse high-performance liquid chromatography. The purified fractions were identified by liquid chromatography–tandem mass spectrometry (LC–MS/MS), and the resulting products were filtered using structure-based virtual screening (SBVS) to obtain 20 peptides. Of those, three noncompetitive inhibitory peptides (DDQIHIF with an IC50 value of 333.5 μmol·L−1, HDWWKER with an IC50 value of 583.6 μmol·L−1, and THDWWKER with an IC50 value of 1291.8 μmol·L−1) were further investigated based on their favorable pharmacochemical properties and ACE inhibitory activity. Molecular docking studies indicated that the three peptides were entirely enclosed within the ACE protein cavity, improving the overall stability of the complex through interaction forces with the ACE active site. The total free binding energies (ΔGtotal) for DDQIHIF, HDWWKER, and THDWWKER were −21.9 Kcal·mol−1, −71.6 Kcal·mol−1, and −69.1 Kcal·mol−1, respectively. Furthermore, a short-term assay of antihypertensive activity in spontaneously hypertensive rats (SHRs) revealed that HDWWKER could significantly decrease the systolic blood pressure (SBP) of SHRs after intravenous administration. The results showed that based on the better antihypertensive activity of the peptide in SHRs, the feasibility of targeted affinity purification and computer-aided drug discovery (CADD) for the efficient screening and preparation of ACE inhibitory peptide was verified, which provided a new idea of modern drug development method for clinical use.

IntroductionKefir grains with efficient proteolytic system is an excellent starter culture for the production of bioactive peptides and milk products. This study explores the casein peptides derived from fermented bovine milk by kefir grains using the peptidomics approaches. The angiotensin converting enzyme (ACE) inhibitory activity of these peptides were also investigated.MethodsAfter fermentation, peptidomics based on the LC-MS/MS was used to investigate the dynamic profile and the structure specificity of generated peptides. The ACE inhibitory activity of peptides was determined by measuring the amount of hippuric acid (HA) by a spectrophotometer at 228 nm.ResultsThe results indicated that the cell envelope proteinases (CEPs) were the PI-/PIII-type. A total of 122 peptides were identified. The β-casein was preferentially hydrolyzed by kefir grains, and the main hydrolysis regions were f57-93, f132-160 and f192-209. The αs1-, and κ-casein were also hydrolyzed by a weaker degree. In the process of fermentation, the accumulated peptides increased with the fermentation time. The fermentation products exhibited ACE inhibitory activity, and this bioactivity remained 63% after simulated gastrointestinal (GI) digestion in vitro. Additionally, 14 Pro-containing peptides with ACE inhibitory activity were also identified.ConclusionThese results provide new insights and evidence to investigate the bioactive milk peptides generated by kefir grains fermentation, as well as a reference for the development of functional foods.

Deep processing of fish skin waste in aquatic products processing can turn waste into treasure in high-value-added way and reduce environmental pollution, and the bioactive peptides from fish skin possess antioxidant, antihypertensive and antibacterial effects, etc. The methods of extraction, separation and identification of bioactive peptides from fish skin waste and their functional activities were discussed in depth, which may provide theoretical basis for the development of food, health products, cosmetics, pharmaceuticals and chemical products. In this paper, the advantages and disadvantages of enzyme, chemical and fermentation methods for the extraction of bioactive peptides from fish skin are reviewed. Compared with chemical methods, enzyme method is widely used, by which the bioactive peptides have higher activity; the cost of fermentation method is low, and it is suitable for mass production. The separation, purification and identification methods of fish skin bioactive peptides, such as ultrafiltration, nanofiltration, gel filtration, ion exchange, high performance liquid chromatography and mass spectrometry are summarized. The combination of multiple separation and identification methods to obtain fish skin bioactive peptides with specific functional activities is the first choice, but to obtain high purity and high activity of the target products is still a difficult breakthrough. In addition, the functional activities of fish skin bioactive peptides, such as antioxidant properties, inhibitory activities of angiotensin converting enzyme (ACE), antibacterial properties, and other bioactivities are analyzed, and the structure-activity relationship between functional activities and molecular weight, sequence structure and location of the peptides is summarized. Finally, the deficiencies of functional activity research, the development of bioactive peptides, and the direction of further research are prospected, aiming to provide reference for the fish processing industry in making high-value functional products. [ABSTRACT FROM AUTHOR]

The macroalga Palmaria palmata could be a sustainable and nutritional food resource. However, its composition may vary according to its environment and to processing methods used. To investigate these variations, wild P. palmata from Quebec were harvested in October 2019 and June 2020, and dried (40 °C, ≃5 h) or stored as frozen controls (−80 °C). The chemical (lipids, proteins, ash, carbohydrates, fibers), mineral (I, K, Na, Ca, Mg, Fe), potential bioactive compound (carotenoids, polyphenols, β-carotene, α-tocopherol) compositions, and the in vitro antioxidant activity and angiotensin-converting enzyme (ACE) inhibition potential of water-soluble extracts were determined. The results suggested a more favorable macroalgae composition in June with a higher content of most nutrients, minerals, and bioactive compounds. October specimens were richer only in carbohydrates and carotenoids. No significant differences in antioxidant or anti-ACE inhibitory activities were found between the two harvest months. The drying process did not significantly impact the chemical and mineral compositions, resulting in only small variations. However, drying had negative impacts on polyphenols and anti-ACE activities in June, and on carotenoids in October. In addition, a concentration effect was observed for carotenoids, β-carotene and α-tocopherol in June. To provide macroalgae of the highest nutritional quality, the drying process for June specimens should be selected. [ABSTRACT FROM AUTHOR]

Sardina pilchardus is a valuable source of bioactive peptides with potential applications in functional foods. In this study, we investigated the angiotensin-converting enzyme (ACE) inhibitory activity of Sardina pilchardus protein hydrolysate (SPH) produced using dispase and alkaline protease. Our results showed that the low molecular mass fractions (<3 kDa) obtained through ultrafiltration exhibited more effective ACE inhibition, as indicated by screening with ACE inhibitory activity. We further identified the low molecular mass fractions (<3 kDa) using an LC-MS/MS rapid screening strategy. A total of 37 peptides with potential ACE inhibitory activity were identified based on high biological activity scores, non-toxicity, good solubility, and novelty. Molecular docking was used to screen for peptides with ACE inhibitory activity, resulting in the identification of 11 peptides with higher -CDOCKER ENERGY and -CDOCKER INTERACTION ENERGY scores than lisinopril. The sequences FIGR, FILR, FQRL, FRAL, KFL, and KLF were obtained by synthesizing and validating these 11 peptides in vitro, all of which had ACE inhibitory activity, as well as zinc-chelating capacity. All six peptides were found to bind to the three active pockets (S1, S2, and S1') of ACE during molecular docking, indicating that their inhibition patterns were competitive. Further analysis of the structural characteristics of these peptides indicated that all six peptides contain phenylalanine, which suggests that they may possess antioxidant activities. After experimental verification, it was found that all six of these peptides have antioxidant activities, and we also found that the SPH and ultrafiltration fractions of SPH had antioxidant activities. These findings suggest that Sardina pilchardus may be a potential source of natural antioxidants and ACE inhibitors for the development of functional foods, and using LC-MS/MS in combination with an online database and molecular docking represents a promising, effective, and accurate approach for the discovery of novel ACE inhibitory peptides. [ABSTRACT FROM AUTHOR]

In this study, changes in angiotensin-I converting enzyme (ACE) inhibitory, a-amylase inhibitory and antioxidant activities, total phenolic content (TPC), total monomeric anthocyanin content (TMAC) of ultrasonic phenolic extracts from pulp and seed of Ziziphus jujuba were investigated during in vitro digestion. Bioaccessible fractions of phenolics in seed and pulp extracts were calculated as 23.24±4.46% and 9.43±0.24%, respectively. Moreover, bioaccessibility for TMAC in seed extracts (147.83±9.20%) was higher than pulp (15.76±3.89%) (P<0.05). A decrease in the antioxidant activity of the extracts occurred after in vitro digestion (P<0.05). The ACE inhibitory activity of undigested extracts from seed (86.04±0.00%) was higher than that of the undigested pulp extract (42.74±8.57%) (P<0.05). The a-amylase inhibitory activity of seed and pulp extracts was determined as 49.18±0.35% and 36.07±5.83%, respectively. The results of the study showed that ACE inhibitory activity and a-amylase inhibitory activity of the polyphenolics from pulp increased after in vitro digestion. [ABSTRACT FROM AUTHOR]

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Stirred-type fruit yoghurts with two different fruit purees (kiwifruit and banana) were produced and were investigated the physicochemical, volatile compounds, 2,2-diphenylpicrylhydrazyl (DPPH) free radical scavenging activity, cupric ion reducing capability (CUPRAC), total phenolic compounds (TPC), angiotensin-converting enzyme (ACE) inhibitory activity, 5-hydroxymethylfurfural (HMF) content, reducing sugar content and microstructure. The addition of fruit puree affected (p0.05). Storage period significantly (p

In this study, selenium (Se)-enriched Moringa oleifera (M. oleifera) seed protein peptides were prepared from Se-enriched M. oleifera seed protein powder by single-factor experiments and response surface optimization, and the Se content, amino acid composition, antioxidant activity, angiotensin-converting enzyme inhibitory (ACEI) activity and xanthine oxidase inhibitory (XOI) activity were evaluated. The results showed that the optimal enzymatic hydrolysis conditions were as follows: time 1.64 h, temperature 37 °C, pH1, enzyme to substrate ratio (E/S) 0.32%, solid to liquid ratio (S/l) 5%. The Se-enriched M. oleifera seed protein peptides prepared under these conditions were rich in essential amino acids (27.65%) and hydrophobicity amino acids (36.28%), and the Se content was 1.78 times that of M. oleifera seed protein, with good free radical scavenging activity against DPPH (IC50 = 4.37 mg/ml) and ABTS (IC50 = 5.45 mg/ml) and excellent cellular antioxidant activity (CAA) against HepG2 cells (EC50 = 0.221 μg/ml). In addition, the peptides had good ACEI activity (IC50 = 2.195 mg/ml) and XOI activity (IC50 = 6.393 mg/ml). This study provides a theoretical basis for the application of Se-enriched M. oleifera seed protein peptides in the development of natural Se-enriched antioxidant, antihypertensive and anti-hyperuricemia functional ingredients. [ABSTRACT FROM AUTHOR]

In recent years, cardiovascular and cerebrovascular diseases have been the focus of several studies. In this study, oyster protein hydrolysate was produced via enzyme hydrolysis and used as a fermentation substrate to ferment recombinant strain PSP2 to produce nattokinase. Using the synergism strategy, fermentation products with fibrinolytic and angiotensin I-converting enzyme (ACE) inhibitory activities were obtained and evaluated. The fermentation medium contained 1.0% trypsin, 1.0% oyster protein hydrolysate, 2.0% maltose, and 0.5% sodium chloride, with an initial pH of 7.0. The maximum nattokinase activity was 390.23 ± 10.24 FU/mL after 72 h of fermentation. The flavor of the product was improved, and heavy metals and volatile salt nitrogen were partially removed via fermentation. The ACE inhibitory activity (IC50) of the fermentation products was 1.433 mg/mL. This study provides a novel approach for the development of marine functional foods with hypotensive and antithrombotic properties. [ABSTRACT FROM AUTHOR]

In this study, physicochemical, biochemical, microstructure, and sensory properties of sheep yoghurts with kiwi and banana added at different rates were investigated. It was determined that the addition of kiwi and banana at different rates increased the amount of ΣMUFA (monounsaturated fatty acids), ΣPUFA (polyunsaturated fatty acids), conjugated linoleic acid (CLA), DPPH (2,2-diphenyl-1-picrylhydrazyl) free radical scavenging activity and the total phenolic compounds (TPC), while decreasing the value of ΣSFA (saturated fatty acids), cholesterol content, acetaldehyde, diacetyl, acetoin, and ACE (angiotensin converting enzyme) inhibitory activities. In addition, the addition of fruit was effective on the homogeneous structure in the microstructure and the amount and depth of the serum pores. As a result of the current research, the production of yoghurt enriched with kiwi and banana at different proportions from sheep milk has shown many positive effects in terms of both nutrition and health. [ABSTRACT FROM AUTHOR]

In the current study, we attempted to use ginger as a novel and natural source of protease in comparison with other commercially available enzymes to extract and characterize antioxidant and antihypertensive hydrolysates from water buffalo liver, a protein rich offal. Hydrolysis of protein extracts from buffalo liver using proteinase-K, pronase-E and ginger protease significantly increased the %degree of hydrolysis (18.5–55%) and generated low-molecular weight peptides evident from SDS-PAGE. Enzyme treated hydrolysates exhibited higher (p < 0.05) DPPH radical scavenging activity (43.7–82.4%) and angiotensin-I-converting enzyme (ACE-I) inhibitory activity (46.9–50.1%) relative to control. Mass spectrometric analysis (MALDI-TOF MS) of selected gel-filtered fractions identified few important peptides derived from nuclear ribonucleoprotein, pyruvate kinase and phosphoglycerate kinase that possess strong antioxidant activity. Present findings indicate the efficacy of partially purified ginger as a novel source of protease in generating protein hydrolysates from water buffalo liver with significant antioxidant and antihypertensive activity in vitro. We successfully demonstrated the recovery of functional bioactive peptides from water buffalo liver which presents a potential opportunity for the meat industries to economically use this important byproduct. [ABSTRACT FROM AUTHOR]

In this study, we studied the bioactive peptides produced by thermolysin hydrolysis of a water-soluble protein (WSP) from the red alga Gracilariopsis chorda, whose major components are phycobiliproteins and Ribulose-1,5-bisphosphate carboxylase-oxygenase (RuBisCo). The results showed that WSP hydrolysate exhibited significantly higher ACE inhibitory activity (92% inhibition) compared to DPP-IV inhibitory activity and DPPH scavenging activity. The phycobiliproteins and RuBisCo of G. chorda contain a high proportion of hydrophobic (31.0–46.5%) and aromatic (5.1–46.5%) amino acid residues, which was considered suitable for the formation of peptides with strong ACE inhibitory activity. Therefore, we searched for peptides with strong ACE inhibitory activity and identified two novel peptides (IDHY and LVVER). Then, their interaction with human ACE was evaluated by molecular docking, and IDHY was found to be a promising inhibitor. In silico analysis was then performed on the structural factors affecting ACE inhibitory peptide release, using the predicted 3D structures of phycobiliproteins and RuBisCo. The results showed that most of the ACE inhibitory peptides are located in the highly solvent accessible α-helix. Therefore, it was suggested that G. chorda is a good source of bioactive peptides, especially ACE-inhibitory peptides. [ABSTRACT FROM AUTHOR]

The goal of this investigation was to find antidiabetic peptides and inhibit angiotensin converting enzyme (ACE) in Lacticaseibacillus paracasei (M11) fermented dromedary camel milk (Camelus dromedaries). According to the findings, the rate of antidiabetic activity increased along with the incubation periods and reached its peak after 48 hr of fermentation. The inhibitions of α‐amylase, α‐glucosidase, and lipase were 80.75, 59.62, and 65.46%, respectively. The inhibitory activity of ACE was 78.33%, and the proteolytic activity was 8.90 mg/mL. M11 at 0.25 mg/mL effectively suppressed LPS‐induced pro‐inflammatory cytokines and their mediators such as NO, TNF‐α, IL‐6, and IL‐1β in RAW 264.7 cells. The rate of inoculum in the optimization phase was 1.5–2.5%, and the greatest proteolytic activity was observed after 48 hr of fermentation. The investigation of the above property in the ultrafiltered fermented milk exhibited the highest antidiabetic and ACE inhibition activities in the 3 kDa than 10 kDa fractions. The molecular weight was determined employing SDS‐PAGE, and the six‐peptide sequences were identified using 2D gel electrophoresis. Due to its high proteolytic activity, the L. paracasei strain has been reported to be useful in the production of ACE‐inhibitory and antidiabetic peptides. Amino acid sequences such from ɑ1, ɑ2, and β‐caseins have been identified within fermented camel milk by searching on online databases, including BIOPEP (for antidiabetic peptides) and AHTPDB (for hypertension peptides) to validate the antidiabetic and ACE‐inhibitory actions of several peptides. Practical applications: The study aims to identify antidiabetic peptides and inhibit ACE in dromedary camel milk fermented with Lacticaseibacillus paracasei M11. Maximum antidiabetic and ACE‐inhibitory actions of the fermented camel milk were observed in 3 kDa permeate fractions. Fermented camel milk significantly reduced the excessive TNF‐α, IL‐6, and IL‐1β production in LPS‐activated RAW 264.7 cells. RP‐LC/MS was used to identify 6 bioactive peptides from dromedary fermented camel milk. This fermented camel milk could be used for the management of hypertension and diabetic related problems. [ABSTRACT FROM AUTHOR]

Five protease-producing and non-mycotoxin-producing fungi (Mucor subtilissimus URM 4133, Mucor sp. URM 4146, Mucor guilliermondii URM 5848, Aspergillus viride-nutans URM 6629 and Penicillium decumbens URM 6018) were used for hydrolysis of caprine casein. Peptides obtained from different fungi were separated on two fractions: molecular mass (MM) < 3 kDa and MM from 3 to 10 kDa, and the peptide fractions were investigated for antimicrobial, antioxidant and antihypertensive bioactive properties. All the 3 to 10 kDa fractions of all fungi were able to inhibit the growth of the three Gram-negative bacteria and the hydrolysate from URM 5848 inhibited all bacteria, except the bacteria Gram-positive Enterococcus faecalis. All hydrolysates with the peptides between 3 and 10 kDa possessed a strong scavenging capacity for ABTS•+ [2,2′-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid)] and DPPH (2,2-diphenyl-1-picrylhydrazyl) radicals, in which URM 5848 (100% and 32%) and URM 4133 (99% and 29%), respectively for (ABTS•+ and DPPH) were the best hydrolysates. The antihypertensive activity was only observed for hydrolysates from the URM 5848 and URM 4133 fungi, and the higher inhibitory effect was observed on fractions < 3 kDa with URM 5848, 19% and URM 4133, 16%. This work was successful in demonstrating the hydrolysates from goat casein by selected fungal proteases are effective in producing different bioactive peptides. [ABSTRACT FROM AUTHOR]

The biological activities of lizardfish viscera sauce under three different fermentation conditions were characterized, and the amino acid profiles of the peptides were investigated to determine their contribution to these biological activities. The lizardfish viscera sauce, with a low salt level prepared under alkaline fermentation conditions of pH 11.0 and 40 °C, had remarkable angiotensin I-converting enzyme (ACE) inhibitory and antioxidant activities, including scavenging of 2.2-diphenyl-1-picrylhydrazy (DPPH), hydroxyl and superoxide anion radicals, and chelating ferric ions. The biological peptides in lizardfish viscera sauce with molecular weights < 3 kDa accounted for more than 50% of its peptide content, ultimately contributing to the biological activities of the fish sauce. The large molecular weight (> 10 kDa) peptides promoted ACE inhibitory activities that might result from the steric hindrance of peptides to block the active site of ACE. Moreover, aliphatic and positively charged amino acid residues in peptides can improve their antioxidant and ACE inhibitory activities. Collectively, our findings indicate the biological activities of fish sauce fermented with a low salt content, and reveal the potential structure–activity relationship of these specific amino acid residues in peptides. [ABSTRACT FROM AUTHOR]

Kenaf (Hibiscus cannabinus L.) seed is a valuable protein source that could be used to prepare protein hydrolysates with antihypertensive properties. However, the potential of using kenaf seeds for health food and pharmaceutical applications has not been fully exploited. Thus, the aim of this study was to identify and characterise the Angiotensin-I-Converting Enzyme (ACE) inhibitory peptides derived from the optimized hydrolysis conditions of kenaf seed protein hydrolysates (KSPH). The optimum hydrolysis conditions determined by response surface methodology (RSM) were as follows: temperature 65 °C, pH 6.5, hydrolysis time 2.25 h, and enzyme/substrate (E/S) ratio of 0.03 (w/w). Under these conditions, the degree of hydrolysis (DH) was 55.28 % and ACE inhibitory activity was 75.51 %. Also, the low molecular weight peptide fractions, <2 kilodalton (kDa) and 2–5 kDa showed the highest ACE-inhibitory activity (82.27 % and 83.69 %, respectively). The 2–5 kDa fraction by Quadrupole-Time-of-Flight Liquid Chromatography-Mass Spectrometry (QTOF LC − MS) revealed the abundance of six peptides, LYWSYLYN, ALFYWVS, LLLHAL, AKSCVVFP, INPPSTTN, and WTIPTPS. Kinetic studies showed that peptide LYWSYLYN possessed the highest Michaelis constant (Km), maximum velocity (Vmax) values and the lowest inhibitor constant (Ki) values, suggesting of its superior ACE inhibitory activity compared to other peptides. [ABSTRACT FROM AUTHOR]

The selenium-rich Moringa oleifera leaves protein was extracted from the selenium-rich Moringa oleifera leaves. The preparation of angiotensin-converting enzyme (ACE) inhibitory peptides from selenium-rich Moringa oleifera leaves was optimized by single factor experiments and response surface method. The ACE inhibitory activity, amino acid composition and selenium content of the optimal enzymatic hydrolysate were analyzed and characterized. The results showed that the optimal hydrolysis conditions of ACE inhibitory peptides were as follows: time 3 h, pH7.5, enzyme to substrate ratio 0.23%, substrate concentration 5.97% and temperature 39.2 ℃. The ACE inhibitory peptides prepared under these conditions showed strong ACE inhibitory activity (IC50=0.522 mg/mL), rich in essential amino acids (24.05%) and hydrophobic amino acids (20.6%), and the selenium content was 1.86 times that of the raw material of Moringa oleifolia leaves. The ACE inhibitory peptides of selenium-rich Moringa oleifolia leaves protein had dual characteristics of functional factor and natural food. This study could provide theoretical basis for the development of antihypertensive drugs and related functional foods.

The proteolytic system of lactic acid bacteria (LAB) could hydrolyze milk casein into small bioactive fragments with angiotensin converting enzyme (ACE) inhibition activity. However, the proteolytic action of LAB differs during the whole fermentation period. This study aims to depict the differentially expressed proteins (DEPs) of proteolytic system in fermented goat milk (FGM) and explore their relationships with ACE inhibition potential. According to the proteomics analysis, the casein transportation was active in the first phase (0–16 h fermentation) while the peptidase was active in the later phase (16–32 h fermentation). LAB intracellular peptidases (pepM, pepX, pepV, pepO, pepT, and pepP) organized a complex PPI network during the later phase. KEGG analysis indicated that the significant protein enrichments were involved in the ribosome and glycolysis/gluconeogenesis. The understanding of protein profiles of LAB proteolytic system during fermentation provides us a new insight on FGM biological characterization and LABs genetic edition. • The protein expressions of fermented goat milk (FGM) with typical ACE inhibitory activity were compared. • The transportation and peptidases expression of lactic acid bacteria (LAB) varied during fermentation. • LAB intracellular peptidases organized a complex PPI network during fermentation. • The significant enrichment pathways of FGM were involved in ACE inhibition potential. [ABSTRACT FROM AUTHOR]

Moringa oleifera (M. oleifera) is considered a medicinal and edible plant with significant health benefits for humans and animals. It is speculated that the antihypertensive effect of M. oleifera leaf is attributed to the inhibition action of protein-derived bioactive components on Angiotensin-I-Converting Enzyme (ACE). In view of this, combined enzymatic hydrolysis was adopted instead of individual enzymatic treatment to prepare ACE inhibitory peptides, and the hydrolysis conditions were optimized from the perspective of ACE inhibitory activity. Following ultrafiltration, QExactive identification, and in silico screening, four novel ACE inhibitory peptides (IPPAYSK, ILVDR, FFFPK, and LLDPR) were collected. The IC 50 values of these peptides ranged from 81.25 to 510.67 μM. In addition, molecular docking simulation and inhibition kinetics were analyzed to explain the inhibition mechanisms. Our study confirms that M. oleifera leaf is a superior source of ACE inhibitory peptides and has potential to serve as ingredients in functional foods for the prevention or management of hypertension. • Combined enzymatic hydrolysis exhibited higher ACE inhibitory activity. • M. oleifera leaf hydrolysates <3 kDa maintained strong ACE inhibitory activity. • Four novel ACE inhibitory peptides were identified. • IPPAYSK, ILVDR and FFFPK exhibited competitive ACE inhibition pattern. • Peptides bound to ACE active sites and Zn2+ through different forces. [ABSTRACT FROM AUTHOR]

Summary: This study aimed to develop fermented spinach juice with enhanced γ‐aminobutyric acid (GABA) level and angiotensin‐converting enzyme (ACE) inhibitory activity and reduced oxalic acid level. We cofermented spinach juice with Levilactobacillus brevis GABA100 and oxalic acid‐degrading bacteria (Lactobacillus gasseri HHuMin D, Lactobacillus sakei RH1114, Lactobacillus acidophilus 19L5, or Limosilactobacillus fermentum BH03). GABA levels were not different among all the fermented juices except for the juice cofermented with L. brevis GABA100 and L. fermentum BH03. Oxalic acid decreased in the cofermented juices. The most increase in ACE inhibitory activity was observed in the juice cofermented with L. brevis GABA100 and L. sakei RH1114. Peptides (IVVGPPPP, PQTETKASVGFKAG and QIIGPVLD) produced during the cofermentation showed a positive correlation with the ACE inhibitory activity of the juice. These results suggest that spinach juice cofermented with L. brevis GABA100 and L. sakei RH1114 may have potential applications for the management of hypertension. [ABSTRACT FROM AUTHOR]

Skipjack tuna (Katsuwonus pelamis) liver (TL) contains high-quality proteins which can potentially serve as an excellent source of functional protein ingredients. Thus, this study was conceptualized to evaluate the physicochemical, functional, and biological properties of proteins from TL using the pH shift process. The pH shift process was conducted through solubilization of TL at pH from 1.5 to 12.5, and the solubilized proteins at pH 2.5, 3.5, 10.5 and 11.5 were precipitated at pH 5.5. Finally, the tuna liver protein powders after the processes at pH 2.5 and 11.5 (TLP 2.5 and TLP 11.5, respectively) were obtained by freeze-drying, i.e. those with the highest extraction and protein recovery yields under acidic and alkaline conditions. Protein and lipid contents of TLPs were higher and lower, respectively, compared to the TL powder (control). Glutamic acid, aspartic acid, and alanine were prominent amino acids found in both TLPs. Foaming properties and water/oil holding capacity were higher in TLP 11.5, while protein solubility and emulsion properties were greater in TLP 2.5 compared between groups. Additionally, the DPPH• and ABTS•+ scavenging activities, as well as the angiotensin I-converting enzyme inhibitory activity, were remarkably higher in TLP 11.5 than in TLP 2.5. On the other hand, significant ferrous-ion chelating activity was observed in TLP 2.5. In conclusion, TLP 11.5 could serve as an alternative functional protein ingredient that provides essential amino acids, functional properties, and bioactivities. [ABSTRACT FROM AUTHOR]

To enhance the value of surimi, efforts have been made to develop a fermentation method with lactic acid bacteria (LAB) to proteolyze fish protein. However, fermenting unheated surimi poses a spoilage risk due to its high bacterial content. Surimi heat treatment can prevent spoilage, but gel formation induced by heating introduces another technical issue: it hinders uniform fermentation. Thus, this study aims to observe the proteolysis and enhance the functionality of seafood product through lactic acid fermentation of kamaboko, a heated surimi. Upon analyzing the kamaboko fermented with Lactobacillus helveticus JCM1004, we observed that LAB produced protease, resulting in the degradation of myosin heavy chain and actin during fermentation. Lactic acid fermentation significantly augmented the peptide content of kamaboko, subsequently elevating the angiotensin Ⅰ-converting enzyme (ACE) inhibitory activity in 200-fold diluted extract of fermented kamaboko to approximately 70% and higher. Notably, our investigation revealed that proteolysis was confined to the surface of kamaboko, as evidenced by SDS-PAGE analysis. This observation implies that the surface area of kamaboko influences the ACE inhibitory activity. Through a comparative analysis of various bacterial strains, we demonstrated that the increase in ACE inhibitory activity is contingent on the protease generated by LAB. These results suggest that LAB-mediated proteolysis of fish proteins liberates bioactive peptides, thereby manifesting in the ACE inhibitory activity. In summary, this study underscores that the fermentation of kamaboko employing proteolytic LAB holds promise in the development of novel functional seafood products.

Ultrasound-assisted enzymolysis has been applied to improve conventional enzymolysis, while there are rare reports on the application of ultrasound to high-concentration feather protein enzymolysis. Therefore, the feasibility of dual-frequency slit ultrasound (DFSU) for enzymolysis of high-concentration hydrolyzed feather meal (HFM), as well as the biological activities and structural characteristics of hydrolysates were investigated. The single-factor test was used to optimize the ultrasonic processing parameters: substrate concentration, frequency mode, intermittent ratio, power density, and time. The results showed that protein recovery rate and conversion rate increased by 6.08% and 18.63% under the optimal conditions (200 g/L, 28/80 kHz, 5:2 s/s, 600 W/L, and 3 h) compared with conventional enzymolysis, respectively. The macromolecular proteins in hydrolysates were converted into micromolecular peptides (< 500 Da) when treated by DFSU, and antioxidant activity and angiotensin-I-converting enzyme (ACE) inhibitory activity of hydrolysates were increased. Scanning electron microscopy (SEM) and atomic force microscopy (AFM) images illustrated the microstructure changes of feather protein particles in the ultrasound-assisted enzymatic hydrolysates of HFM (UEH), including more porous, smaller, and more uniform. Additionally, the conformation of protein molecules was significantly affected (P

The macroalga Palmaria palmata could be a sustainable and nutritional food resource. However, its composition may vary according to its environment and to processing methods used. To investigate these variations, wild P. palmata from Quebec were harvested in October 2019 and June 2020, and dried (40 °C, ≃5 h) or stored as frozen controls (−80 °C). The chemical (lipids, proteins, ash, carbohydrates, fibers), mineral (I, K, Na, Ca, Mg, Fe), potential bioactive compound (carotenoids, polyphenols, β-carotene, α-tocopherol) compositions, and the in vitro antioxidant activity and angiotensin-converting enzyme (ACE) inhibition potential of water-soluble extracts were determined. The results suggested a more favorable macroalgae composition in June with a higher content of most nutrients, minerals, and bioactive compounds. October specimens were richer only in carbohydrates and carotenoids. No significant differences in antioxidant or anti-ACE inhibitory activities were found between the two harvest months. The drying process did not significantly impact the chemical and mineral compositions, resulting in only small variations. However, drying had negative impacts on polyphenols and anti-ACE activities in June, and on carotenoids in October. In addition, a concentration effect was observed for carotenoids, β-carotene and α-tocopherol in June. To provide macroalgae of the highest nutritional quality, the drying process for June specimens should be selected.

Sardina pilchardus is a valuable source of bioactive peptides with potential applications in functional foods. In this study, we investigated the angiotensin-converting enzyme (ACE) inhibitory activity of Sardina pilchardus protein hydrolysate (SPH) produced using dispase and alkaline protease. Our results showed that the low molecular mass fractions (Sardina pilchardus may be a potential source of natural antioxidants and ACE inhibitors for the development of functional foods, and using LC-MS/MS in combination with an online database and molecular docking represents a promising, effective, and accurate approach for the discovery of novel ACE inhibitory peptides.

Tryptic WPHs with considerable residual whey protein content intact were developed from two sheep/goat WPCs (65% and 80% protein) without pH control. Pasteurization was used to avoid denaturation. Changes in non-protein nitrogen (DH_TCASN), free amino groups (DH_TNBS), and major whey proteins were used to investigate the degree and extent of hydrolysis. Antihypertensive potential (ACE-IA), radical scavenging (DPPH-RSA), and iron chelation (Fe-CA) were assessed. No statistically significant changes in pH (5.84–6.29) were observed during hydrolysis and storage. At the start of hydrolysis, DH_TCASN was ≅11% for both substrates whereas DH_TNBS was >10% and >5% for WP65 and WP80, respectively. After one-hour hydrolysis, DH_TCASN was ≅17% for both substrates and DH_TNBS was ≅15% and ≅11% for WP65 and WP80, respectively. The β-lactoglobulin, α-lactalbumin, and caseinomacropeptide of WP65 were hydrolyzed by 14 ± 1.3%, 73.9 ± 2.6% and 37 ± 2.6%. The respective values for WP80 were 14.9 ± 1.7%, 79.9 ± 1%, and 32.7 ± 4.8%. ACE-IA of the hydrolysates of both substrates was much higher (>80%) than that of controls (<10%). Hydrolysis, substrate type, and storage did not affect the DPPH-RSA (45–54%). Fe-CA of the WP65 and WP80 hydrolysates were ≅40% and ≅20%, respectively; a similar outcome was found in the respective controls. Refrigerated storage for 17 h did not affect the degree of hydrolysis and biofunctional activities. [ABSTRACT FROM AUTHOR]

The physicochemical, structural properties, antioxidant, and angiotensin I-converting enzyme (ACE) inhibitory activities of fish skin protein hydrolysate (SPH) that were freeze-dried (SPH-FD) and spray-dried (SPH-SD) were investigated. SPH-SD showed abundant volatile compounds, higher DPPH radical scavenging activity and ferrous iron chelating activity than SPH-FD, while the ABTS radical scavenging activity and ACE inhibitory activity were not influenced by the drying method. Amino acid compositions showed a higher proportion of proline and hydroxyproline residues in SPH-FD. The major molecular weights were both distributed below 1000 Da. SPH-SD had spherical structures, while SPH-FD had glass shard-like structures. The results indicated that the drying method could affect the physicochemical properties of hydrolysates, and SPH-SD showed potential prospects in developing functional fortified foods. [ABSTRACT FROM AUTHOR]

The study aimed to investigate potent antioxidant activities (ABTS assay, Hydroxyl free radical scavenging assay, and Superoxide free radical assay), ACE inhibitory activity, and anti-inflammatory activity in the WPC (whey protein concentrate) hydrolysate using Alcalase. The hydrolysis conditions (addition rate and incubation times) for peptide synthesis were also optimized using proteolytic activity. The generation of proinflammatory cytokines by lipopolysaccharide-treated murine macrophages was reduced when the protein hydrolysate concentration was low. In comparison to unhydrolyzed WPC, SDS-PAGE examination revealed no protein bands in WPC hydrolysates. Two-Dimensional (2D) gel electrophoresis did not show any protein spots. Using the 'In-solution trypsin digestion' approach, the trypsin digested protein samples were put into RPLC/MS for amino acid sequencing. Peptides were also identified using RPLC/MS on fractions of 3 and 10 kDa permeates and retentates. The MASCOT database was used to look up the raw masses of LC/MS. By comparing hydrolyzed whey protein to the BLASTp (NCBI), PIR, BIOPEP, and AHTPDB databases, novel antioxidative and ACE inhibitory peptides were reported. [ABSTRACT FROM AUTHOR]