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Copyright of Modern Food Science & Technology is the property of Editorial Office of Modern Food Science & Technology 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.)

This study investigated the effects of ultrasound and microwave and their combinations on preserving the quality of litchi juice during 21 days of storage. The physiochemical analysis exhibited that, the pH and Vitamin C content decreased gradually, whereas TSS, TA, and color values increased over the storage period. It was observed that the synergistic approach of sonication and microwave had positively impacted the bioactive components of fresh litchi juice. The results indicate that the total phenolic content (TPC), total flavonoid content (TFC), and antioxidant properties of fresh litchi juice were changed significantly (p≤0.05) and reduced with increases in the treatment time. For instance, combined treatment (T6) exhibited the TPC (81.84±0.72 to 55.74±0.47 mg GAE/100 mL of juice) and TFC (3.31±0.136 to 3.12±0.126 mg QE/100 mL of juice) for 0 to 21 days of storage. On the other hand, the DPPH radical scavenging activity of litchi juices was increased notably (p≤0.05) and subsequently decreased after treatments, where the values ranged between 106.35±0.66 to 123.42±1.09 mg AAE/100 mL of juice at initial storage. The highest microbial growth inhibition was found in T6, and the values were (4.05-5.01 log10 cfu/mL) for total plate count and (3.63-4.78 log10 cfu/mL) for total yeast and mold during initial storage. Therefore, the combined treatment of sonication and microwave could be employed without chemical preservatives to treat fresh litchi juice with better retention of physicochemical attributes and bioactive phytochemicals.

The effects of dimethyl dicarbonate (DMDC), mild heat and their combination on the microorganisms and physicochemical indices of litchi juice were compared. The results showed that the sterilization effect of DMDC alone or mild heat alone was poor, whilst the number of residual microorganisms in the litchi juice treated by the combination was the lowest, with the total number of colonies and lactic acid bacteria being 0.41 and 0.36 lg CFU/mL, respectively, and no yeast and mold being detected. Compared to fresh litchi juice, DMDC treatment had no effect on the quality of Litchi juice, and the changes in ascorbic acid content and color of the mild heat alone group and the combined treatment group were insignificant, causing the increases in the total phenolics (total flavonoids) by 40.16% (7.16%) and 38.01% (4.35%), respectively, and increases in the ferric ion reducing antioxidant power (DPPH free radical scavenging ability) by 15.55% (11.85%) and 7.61% (3.71%), respectively. These results indicated that mild heat could promote the release of phenolics and improve the antioxidant activity. Correlation analysis showed that the ΔE of litchi juice was negatively correlated with Vc content, and the antioxidant activity was positively correlated with the contents of total phenolics and total flavonoids. Cluster heat map analysis and sensory evaluation revealed that the combined treatment could promote the release of flavor substances without causing a pronounced cooking flavor. The total number of colonies in the combined treatment group stored at 4 °C for 21 days was less than 100 CFU/mL. In conclusion, the combination of mild heat and DMDC treatment led to a good sterilization effect on the microorganisms in the litchi juice without causing adverse effects, and the shelf life of the juice was up to 21 d. This study provides a scientific basis for the industrialization of high-quality litchi juice. [ABSTRACT FROM AUTHOR]

Levilactobacillus brevis strains can be isolated from traditional Chinese pickles and used as the starter cultures to improve the nutritional profiles of fermented juices. Three L. brevis strains (LBG-29, LBG-24, LBD–14) that produce high levels of gamma-aminobutyric acid (GABA; >300 mg/L) were isolated from traditional Chinese pickles. The strains showed tolerance to low pH and high bile salts and exhibited safety in vitro. Litchi juice was fermented using each strain at 37 °C for 48 h. The litchi juice was determined to be a good substrate for fermentation as the process enhanced its functional profile. Overall, cell vitality increased (above 8.7 log10 CFU/mL), the antioxidant activities of 2,2-diphenyl-1-picrylhydrazyl (DPPH) and ferric ion-reducing antioxidant power (FRAP) were significantly increased, and the antioxidant capacity of the 2,2′-amino-di(3-ethyl-benzothiazoline sulphonic acid-6)ammonium salt (ABTS) was decreased. There was also a significant increase in the GABA and acetic acid content after LBG-29 and LBG-24 fermentation. It was thus determined that the LBG-29 and LBG-24 strains could be used to improve beverage functionality and aid in the development of new products. This is the first report of litchi fermentation using L. brevis as a starter culture. Further research is required to elucidate the functional benefits for the human body and the nutritional and functional properties during its shelf life. [ABSTRACT FROM AUTHOR]

Three Lactobacillus Plantarum (LP), namely LP28, LP226 and LPC2W, were employed to investigate the effect on the aroma profiles of pasteurized litchi juice using E-nose, GC-IMS, GC-MS, and sensory evaluation. The E-nose results showed that pasteurization weakened the flavor profile of litchi juice, while LP fermentation effectively promoted flavor formation. The GC-MS analysis demonstrated that pasteurization significantly reduced the content of alcohols (28.51%), especially geraniol and citronellol, which give litchi juices a fruity and floral aroma. Different LP fermentation enhances the characteristic aroma and produces some new compounds that give it a strong fruity and citrus-like aroma. Moreover, 37 aroma-active compounds (OAV>1) indicated that the linalool (OAV 7504) was the highest, followed by (Z)-rose oxide (OAV 4265), 1-octen-3-ol (OAV 1055) and geraniol (OAV 764), which jointly form the main characteristic flavor. More esters were identified by GC-IMS, indicating the advantage of the combined approach for a better understanding of the impact of pasteurization and fermentation on the litchi juice. The sensory evaluation confirmed that the aroma attributes of fruity, citrus-like, floral, sweet and litchi-like were stronger for the samples fermented by LP28 than those for the other samples. The combination strategy used in this study would facilitate the awareness of litchi juice aroma and broaden our insight into the deep processing of litchi.

Levilactobacillus brevis strains can be isolated from traditional Chinese pickles and used as the starter cultures to improve the nutritional profiles of fermented juices. Three L. brevis strains (LBG-29, LBG-24, LBD–14) that produce high levels of gamma-aminobutyric acid (GABA; >300 mg/L) were isolated from traditional Chinese pickles. The strains showed tolerance to low pH and high bile salts and exhibited safety in vitro. Litchi juice was fermented using each strain at 37 °C for 48 h. The litchi juice was determined to be a good substrate for fermentation as the process enhanced its functional profile. Overall, cell vitality increased (above 8.7 log10 CFU/mL), the antioxidant activities of 2,2-diphenyl-1-picrylhydrazyl (DPPH) and ferric ion-reducing antioxidant power (FRAP) were significantly increased, and the antioxidant capacity of the 2,2′-amino-di(3-ethyl-benzothiazoline sulphonic acid-6)ammonium salt (ABTS) was decreased. There was also a significant increase in the GABA and acetic acid content after LBG-29 and LBG-24 fermentation. It was thus determined that the LBG-29 and LBG-24 strains could be used to improve beverage functionality and aid in the development of new products. This is the first report of litchi fermentation using L. brevis as a starter culture. Further research is required to elucidate the functional benefits for the human body and the nutritional and functional properties during its shelf life.

Copyright of Journal of Food Safety & Quality is the property of Journal of Food Safety & Quality Editorial Department 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.)

Summary: In this paper, Lactobacillus casei growth, sugar utilisation, exopolysaccharides (EPSs) formation and EPSs characterisation during fermentation of milk with or without litchi juice were evaluated. During L. casei fermentation of litchi‐milk samples, the EPSs content increased with the increase of litchi juice levels (0–25%, v/v), and the both relationship appeared in S‐type curve. The viscosity of fermented milk also significantly increased with the formation of EPSs, and which positively correlated with the EPSs content (R2 = 0.9782). The EPSs from the fermented litchi‐milk samples was isolated for further structural characterisation. Monosaccharide and molecular weight analysis of purified EPSs sample proved that it contained no carbohydrate other than glucose, and its molecular weight was calibrated as 3.03 × 106 Da. FT‐IR and NMR (1H and 13C) spectroscopy analysis confirmed the synthesised EPSs sample was α‐glucans (dextrans) with mainly α‐(1→6) linkages. To the best of our knowledge, this is the first study to report that litchi juice can enhance the EPSs (dextrans, mainly α‐(1→6) linkages) production in fermented milk. In this paper, the effect of litchi juice on exopolysaccharide production in milk fermented by Lactobacillus casei were evaluated. Litchi juice can enhance the exopolysaccharides (dextrans, mainly α‐(1→6) linkages) production in fermented milk. And the viscosity of fermented milk also significantly increased with the formation of exopolysaccharides. [ABSTRACT FROM AUTHOR]

Copyright of Shipin Kexue/ Food Science is the property of Food Science Editorial Department 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.)

Spray drying of probiotic Lactobacillus plantarum in litchi juice with varied proportion of maltodextrin, fructooligosaccharide (FOS) and pectin was performed to determine the effect on cell viability. The spray dried powders were investigated for physical, physicochemical and toxicological properties and survivability of cells in simulated gastric and intestinal digestion. The results showed that coating material comprising of maltodextrin 10% (w/v) and 5% (w/v) FOS gave highest yield and survivability of the encapsulated bacteria. This composition of the coating material also showed good solubility, low water activity, satisfactory colour, uniform particle size with smooth surface. Powder coated with 10% (w/v) maltodextrin and 5% (w/v) pectin showed reduced powder properties and cell viability even though had the highest glass transition temperature. Maltodextrin at 10% (w/v) and FOS at 5% (w/v) levels in the coating material can be considered as the optimal carrier material composition for protection of the bacterial cells from damage by adverse environmental conditions of spray drying and for possessing desirable powder characteristics. This combination also provided protection to bacterial cells in gastric environment and also enhanced their growth in simulated digestive system. [ABSTRACT FROM AUTHOR]

A fungus J2 producing laccase with high yield was screened in soils and identified asAbortiporus biennis. The production of laccase was induced by 0.1 mM Cu2+, 0.1 mM tannic acid, and 0.5 M ethanol. The laccase fromAbortiporus biennisJ2 was purified to electrophoretic homogeneity by a couple of steps. The N-terminal amino acid sequence of the enzyme was AIGPTADLNISNADI. The properties of the purified laccase were investigated. The result showed the laccase fromAbortiporus biennisJ2 is a thermo and pH stable enzyme. The laccase activity was inhibited by Hg2+, Cd2+, Fe2+, Ag+, Cu2+, and Zn2+, while promoted by Mg2+, Mn2+at 10 mM level. Purified laccase was used to the clarification of litchi juice. After treatment with this laccase, the phenolic content of litchi juice had been found to be greatly reduced along with an increase in the clarity of the juice. The result indicated the potential of this laccase for application in juice procession. [ABSTRACT FROM AUTHOR]

Three Lactobacillus Plantarum (LP), namely LP28, LP226 and LPC2W, were employed to investigate the effect on the aroma profiles of pasteurized litchi juice using E-nose, GC-IMS, GC-MS, and sensory evaluation. The E-nose results showed that pasteurization weakened the flavor profile of litchi juice, while LP fermentation effectively promoted flavor formation. The GC-MS analysis demonstrated that pasteurization significantly reduced the content of alcohols (28.51%), especially geraniol and citronellol, which give litchi juices a fruity and floral aroma. Different LP fermentation enhances the characteristic aroma and produces some new compounds that give it a strong fruity and citrus-like aroma. Moreover, 37 aroma-active compounds (OAV>1) indicated that the linalool (OAV 7504) was the highest, followed by ( Z )-rose oxide (OAV 4265), 1-octen-3-ol (OAV 1055) and geraniol (OAV 764), which jointly form the main characteristic flavor. More esters were identified by GC-IMS, indicating the advantage of the combined approach for a better understanding of the impact of pasteurization and fermentation on the litchi juice. The sensory evaluation confirmed that the aroma attributes of fruity, citrus-like, floral, sweet and litchi-like were stronger for the samples fermented by LP28 than those for the other samples. The combination strategy used in this study would facilitate the awareness of litchi juice aroma and broaden our insight into the deep processing of litchi., Competing Interests: The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (© 2023 The Authors.)

The present study compared physicochemical parameters, total phenolic and total flavonoid contents, individual phenolics, and antioxidant activity of litchi juice processed by high pressure carbon dioxide (HPCD), high temperature and ultra high temperature treatments. The results showed that HPCD can retain color of litchi juice better than thermal processing (p < 0.05), while three processing methods had no influence on pH and total soluble solid in litchi juice. Compared to thermal processing, HPCD processed litchi juice had more total phenolics, total flavonoid and individual phenolics including rutin, (-)-epicatechin and chlorogenic acid (p < 0.05). Furthermore, the antioxidant activity of litchi juice was analyzed by 2,2-diphenyl-l-picrylhydrazyl (DPPH), ferric reducing antioxidant power (FRAP) and 2,2'-azinobis-(3-ethylbenzthiazoline-6-sulphonate) (ABTS) assays. The result indicated that HPCD processing can preserve the antioxidant activity better than thermal processing (p < 0.05). This study suggested that HPCD could be used as an alternative of traditional thermal processing to produce more fresh fruit juice. [ABSTRACT FROM AUTHOR]

The aim of this study was to evaluate the use of litchi juice treated by high hydrostatic pressure (HHP) as substrates for producing a probiotic beverage by Lactobacillus casei. The quality attributes and product stability of fermented heat- and HHP-treated litchi juice by L. casei were compared. Compared with fermented heat-treated litchi juice, fermented HHP-treated litchi juice showed a better color, flavor and overall acceptance, and also retained more total phenolics and antioxidant capacity. Both viability counts of L. casei were more 8.0logCFU/mL in heat- and HHP-treated litchi juice after 4weeks of storage at 4°C. Besides, some quality attributes in fermented heat- and HHP-treated litchi juice showed the tendency to slow decrease during storage at 4°C, but both scores of overall acceptance of fermented heat- and HHP-treated litchi juice showed no reduction after the storage of 4weeks at 4°C. Overall, the application of HHP treatment could be an ideal alternative of heat treatment to ensure the microbial safety, consistent sensory and nutritional quality of fermented litchi juice prior to fermentation. Industrial relevance: The study is relevant to fermentation of litchi juice by probiotic L. casei. In this study, results shown the application of high hydrostatic pressure (HHP) treatment could be an ideal alternative of heat treatment to ensure the microbial safety, consistent sensory and nutritional quality of fermented litchi juice prior to fermentation. [ABSTRACT FROM AUTHOR]

This study investigated the effects of dimethyl dicarbonate (DMDC) on the fermentation of litchi juice by Lactobacillus casei as an alternative of heat treatment that may have undesirable effect on the juice. Quality attributes and products stability of both the fermented heat- and DMDC-treated litchi juice by L. casei were compared. It was found that residual indigenous microorganisms in both the heat- and DMDC-treated litchi juice cannot grow into dominant bacteria during further fermentation of litchi juice by L. casei. Compared with fermented heat-treated litchi juice, fermented DMDC-treated litchi juice showed a better color, flavor, and overall acceptance, and also retained more total phenolics and antioxidant capacity. The viability counts of L. casei in both the heat- and DMDC-treated litchi juice were more 8.0 lg CFU/mL after 4 wk of storage at 4 °C. Also, some quality attributes in both the fermented heat- and DMDC-treated litchi juices, including pH, total phenolics, ascorbic acid, antioxidant capacity, and so on, showed the tendency to slow decrease during storage at 4 °C, but the scores of overall acceptance showed no reduction after the storage of 4 wk at 4 °C. On the whole, the application of DMDC treatment could be an ideal alternative of heat treatment to ensure the microbial safety, consistent sensory, and nutritional quality of fermented litchi juice prior to fermentation. Practical Application The pasteurization treatment is often recommended prior to fermentation of fruit juice by probiotics, as it would lead to a rapid inactivation and inhibition of spoilage and pathogenic bacteria, and ensure the fermented products with consistent sensory and nutritional quality. Dimethyl dicarbonate (DMDC) is a powerful antimicrobial agent, which was approved for use as a microbial control agent in juice beverages by FDA. This study provides a scientific basis for the application of DMDC prior to fermentation of litchi juice. [ABSTRACT FROM AUTHOR]

The individual and combined influences of dimethyl dicarbonate (DMDC) and nisin (200 IU/mL) at mild heat on the inactivation of indigenous microorganisms in litchi juice, including bacteria, molds and yeasts (M&Y), were investigated. The fresh litchi juice with or without nisin were exposed to 250 mg/L DMDC at 30, 40, or 45 °C for 0.5, 1, 2, 3, 4, or 6 h. A complete inactivation of M&Y in the litchi juice with or without nisin was achieved as exposed to 250 mg/L DMDC at 30, 40, or 45 °C for 0.5 h. The bacteria, especially Bacillus sp. and Leuconstoc mesenteroides showed higher resistance than M&Y in the litchi juice. Bacillus sp. and Leuconstoc mesenteroides in the litchi juice was not completely inactivated by 250 mg/L DMDC at 30, 40, or 45 °C. However, nisin addition can enhanced the inactivation of these bacteria by DMDC, and nisin and DMDC also showed a synergistic effect on the inactivation of bacteria. M&Y and bacteria were not detected in the litchi juice added with 200 IU/mL nisin as exposed to 250 mg/L DMDC at 45 °C for 3 h. In addition, microbial shelf life of the litchi juice during storage at 4 °C also was evaluated as treated by 250 mg/L DMDC or combination with nisin at 45 °C for 3 h. [ABSTRACT FROM AUTHOR]

Abstract: The individual and combined effects of high-pressure carbon dioxide (HPCD), mild heat (MH) and nisin (200 ppm) on the inactivation of natural microorganisms, including aerobic bacteria (AB), yeasts and molds (Y&M), in litchi juice were evaluated. The samples were treated at a pressure of 10 MPa and temperatures of 32, 42 or 52 °C for 5, 10, 15, 20, 25 or 30 min. Temperature played a prominent role in the inactivation of both AB and Y&M when combined with HPCD, particularly for AB at 52 °C and Y&M at temperatures ≥42 °C. Nisin increased the susceptibility of AB to the combined treatment of HPCD and MH (HPCD + MH). A reduction of 4.19 log cycles was achieved by HPCD + MH at 52 °C for 15 min, and complete inactivation of AB was obtained by combination of HPCD, MH and nisin (HPCD + MH + nisin). No significant effect of nisin was found on the inactivation of Y&M. [Copyright &y& Elsevier]

Litchi pulp was treated with various concentration levels of hydrolytic enzymes viz. pectinase (0-0.133%w/w), cellulase (0-0.266%w/w) and hemicellulase (0-0.20%w/w) for different durations (30-150 min) at 45°C. The effect of enzyme treatment conditions was studied on yield, clarity, apparent viscosity and total soluble solids (TSS) of juice obtained from the pulp. The optimum process conditions were determined by employing a second order central composite rotatable design in combination with response surface methodology. Yield, clarity and TSS of juice were found to increase and apparent viscosity was found to decrease significantly by enzymatic treatment. The optimum conditions for enzymatic treatment of pulp obtained after a 2 sided desirability function with the responses juice yield, clarity and TSS to be maximized and viscosity to be minimized were 0.076% (w/w) pectinase, 0.138% (w/w) cellulase, 0.107% (w/w) hemicellulase and incubation time of 106.5 min. The predicted values for juice yield, clarity, viscosity and TSS under optimized conditions were 77.19%, 93.53%, 1.359mPa s and 19.68°brix which showed a good agreement with the experimental values under same set of conditions. [ABSTRACT FROM AUTHOR]

Probiotic litchi juice has the function of improving immune regulation and reshaping gut microbiota composition. • This is the first report about the effects of FL on immunomodulatory function and gut microbiota in mice. • The probiotic abilities of FL were dramatically increased after fermentation with L. casei. • FL significantly helped mice to prevent the decrease of immunity. • FL could protect the intestinal tract and ameliorate gut microbiota composition of mice. Development new functional foods containing probiotics had gained much attention during the past two decades. In this study, probiotic litchi juice was developed, and its effects on immunomodulatory function and gut microbiota were evaluated. Firstly, the litchi juice was fermented with Lactobacillus casei , which increased total phenolic, total flavone, and exopolysaccharide contents of the litchi juice. Hence, the immunomodulatory influence of fermented litchi juice (FL) was investigated in cyclophosphamide-induced mice. The results showed that FL enhanced immune organs indexes (spleen, thymus) and antioxidant capacity, improved the secretions of cytokines (IL-2, IL-6) and immunoglobulins (IgA, IgG, SIgA), and protected the intestinal tract. Finally, the effect of FL on gut microbiota was analyzed by high-throughput sequencing analysis. The changes in the relative abundance of dominant microbe were investigated at phylum and genus levels, respectively. After treatment with FL, the relative abundance of Firmicutes phylum was dramatically increased, as well as the genera of Faecalibaculum , Lactobacillus , and Akkermansia. These findings indicated that probiotic litchi juice could alleviate immune dysfunction and modify gut microbiota structure of mice, which provide a potential functional food to improve the host health. [ABSTRACT FROM AUTHOR]