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Meat is an important part of the daily human diet, and its quality is essential for consumers' health and taste experience. During the transformation from carcass to meat and meat processing after animal slaughter, many complex biochemical reactions occur, among which protein oxidation plays an important role in the formation of meat quality. Based on the influence of protein oxidation on meat quality, the relationship between protein oxidation and changes in meat quality under factors such as the types of protein oxidation products, processing methods and conditions is summarized in this review, which will provide a theoretical basis for reducing the oxidation of meat protein, and a scientific guidance for practical production.

Iron is an essential nutrient for maintaining red blood cell metabolism and assisting bone marrow hematopoiesis. Iron deficiency can cause various diseases, such as anemia, stunted growth, and premature birth in pregnant women. As a new iron supplement product, peptide iron chelate has been used as a new ideal iron supplement in recent years because of its advantages of high absorption rate, safety, and no side effects. This paper mainly reviews the preparation of foodborne peptides and peptide iron chelates and the factors affecting their chelation activity, explored the iron-binding mechanism of peptides, summarizes their binding sites and chelation patterns, further analyzes their conformational changes and intermolecular forces, and summarizes how they promote iron bioavailability. The aim is to provide a reference for developing and applying iron peptide chelates in functional foods and new iron supplements.

To investigate the effects of different extraction processes on the physicochemical properties and volatile flavor compounds of chicken oil. This study used three different extraction processes, namely dry, wet and microwave to extract chicken oil. The physicochemical properties of chicken oil extracted by different processes were comprehensively compared. At the same time, the volatile substance composition was determined by headspace gas chromatography-mass spectrometry, and the key volatile flavor component composition differences in chicken oil extracted by different processes were established by combining relative odor activity values, principal component analysis, and cluster analysis. The results showed that the chicken oil cooked by dry method had the lowest brightness, a redder and yellower color, and a lower content of malondialdehyde. Wet cooking chicken oil had the highest brightness, a greenish or yellowish color, and a lower acid value. The chicken oil cooked by microwave had a slightly darker brightness, lighter yellow and red, higher extraction rate, better oxidation stability, and shorter cooking time. A total of 49 volatile flavor compounds were identified in chicken oil samples extracted using different extraction methods. Among them, 39, 41, and 44 volatile flavor compounds were extracted from chicken oil using dry, wet, and microwave methods, respectively, with a total of 30 volatile flavor compounds. By combining ROAV and PCA, (E,E)-2,4-heptadienal, 1-octen-3-ol, hexanal, (E)-2-deceenal, 1-pentanol, octanal, (E,E)-2,4-decadienal, and 3-methylbutanal were identified as the main characteristic flavor compounds of chicken oil. The characteristic flavor substances extracted from chicken oil by microwave method had a high content and a variety of types. This study indicated that microwave technology had the advantages of relatively short time consumption, high yield, good oxidation stability and high content with variety of characteristic flavor substances in chicken oil, making it a worthwhile approach for further research and exploration of chicken oil extraction.

To efficiently utilize chicken blood, one of the by-products of broiler chickens, the fresh chicken blood was as the main raw material in this study. The peak area of immobilized water in low field nuclear magnetic field was used as the evaluation standard. The effect of different varieties and concentrations of anti-freezing amendments was investigated in the peak area of immobilized water for the frozen chicken blood tofu. Moreover, the preparation process of frozen chicken blood tofu was optimized by response surface design. Furthermore, the water loss rate, texture and color index were analyzed in the optimized frozen chicken blood tofu, which could provide scientific basis for the development of frozen chicken blood tofu products. The results showed that the optimized preparation process of frozen chicken blood tofu was as follows, 0.1% (w/v) of sodium fatty acyllactate, 0.1% (w/v) of potassium alginate, and 2% (w/v) of cassava modified starch. Under this process condition, the low-field nuclear magnetic non-flowing water peak area of frozen chicken blood tofu was 2143, which was the largest compared with the blank group and other treated groups. Therefore, the water retention effect in this study was best. The hardness, chewability, gelability and brightness of the optimized frozen chicken blood tofu were significantly (P

This paper was aimed to improve sausage quality by adding non-meat protein. The effects of adding of four non-meat proteins: Spray-dried blood cells (SBC), soybean protein isolate (SPI), egg white protein (EWP), and porcine plasma protein (PPP) on the quality of Nanjing sausages were investigated. The sensory properties, cooking loss, pressure juice loss, water activity, color difference, chewiness, and microstructure were analyzed. The results showed that among these 4 proteins, the sensory quality and chewiness of Nanjing sausage products were overall improved by adding EWP, in which chewiness was increased by 14.73% compared to the control group. The sausages by adding PPP was significantly increased the water-retaining property, where the steaming loss rate and pressure loss rate was decreased by 13.31% and 55.79%, respectively. The low-field NMR results of sausages by adding SPI and PPP showed that a tendency for T21 was left-shifted. The addition of SBC to sausages was significantly (P

To evaluate the potential of chicken blood for dietary iron supplementation, chicken blood and ferrous chloride were used as raw materials to prepare iron-chelating peptides from chicken blood in this paper. The structure of iron-chelating peptides from chicken blood was characterized by scanning electron microscopy and differential scanning calorimetry. The stability of iron-chelating peptides from chicken blood was analyzed at different temperatures (30~80 ℃) and pH (2~9), and its in vitro stability was also discussed. The study confirmed that it had good thermal stability (iron retention rate above 73.76%) and acid and alkali resistance. The digestive stability of iron-chelating peptides from chicken blood (iron retention of 86.01%) was found to be better than that of ferrous sulfate and ferrous gluconate by simulated digestion in vitro. In addition, under the influence of three dietary factors, namely 1% phytic acid, 1% oxalic acid, and 8% dietary fiber, iron-chelating peptides from chicken blood showed better bioaccessibility than ferrous sulfate and ferrous gluconate.

In the study, variations of physicochemical factors, lipoxygenase (LOX) and hydroxyl octadecanodienoic acid (HODEs) were investigated during manufacturing of traditional salted meat, and the relationship between LOX and HODEs was studied and the evolution of lipids oxidation was tentatively discussed. The results indicated that LOX activity increased at salting stage, followed by decreasing continuously during the salted meat manufacturing. The total amount of HODEs increased slowly, while the ratio of 13-HODEs/9-HODEs decreased from 1.31 to 1.13. There was a significantly positive correlation between LOX activity and the ratio of 13-HODEs/9-HODEs (r=0.942, P

To investigate the effects of different packaging methods on microbial composition of chilled chicken during storage, the microbial diversity was analyzed by Illumina MiSeq high-throughput sequencing. The results showed that the modified atmosphere packaging (MAP), the vacuum packaging (VP) and the nitrogen-filled packaging (N2) could significantly reduce the number of microorganisms and volatile base nitrogen during refrigeration at 4 °C compared with the pallet packed (PP) group. High-throughput sequencing showed that the bacterial species richness of chilled chicken was high in the early stage of storage. The dominant bacteria of chilled chickens in PP group at the later stage of storage were Pseudomonas, Brochothrix, Acinetobacter and Shewanella. It indicated that they could tolerate lower temperatures. Compared with the PP group, the abundance of Pseudomonas and Acinetobacter in MAP group decreased by 14.8% and 9.2%, respectively, while nitrogen-filled packaging reduced the abundance of Acinetobacter and Shewanella. by 9.6% and 7.4%, respectively. The abundance of Acinetobacter and Brochothrix decreased significantly by 8% and 5.6% after vacuum packaging. Different packaging methods could have a greater impact on the flora in chilled chicken meat. All three types of packaging could inhibit the growth of Acinetobacter and MAP had a better inhibitory effect on Pseudomonas, while nitrogen-filled packaging and vacuum packaging had a better inhibitory effect on Shewanella and Brochothrix. This study also provides a theoretical basis for the future packaging methods used in chilled chicken meat.

Calcium is an essential nutrient and plays an important role in life and health. Insufficient calcium intake in the body can lead to kinds of diseases, such as rickets and osteoporosis. As more and more calcium chelated peptides are prepared from food in recent years, the advantages of calcium chelated peptides like good stability and high bioavailability have attracted much attention and calcium chelated peptides have been reported to be a kind of ideal calcium supplements. In this paper, the research progress of calcium chelted peptide is summarized, the preparation, separation and purification methods of calcium chelted peptide are introduced, the factors affecting its chelating ability are analyzed, and the ways to promote the bioavailability of calcium are also discussed, in order to provide help for the development and utilization of calcium chelted peptide in functional foods in the future.

Bile salt hydrolase (BSH) is an intracellular enzyme which is produced by intestinal flora during the period of growth and reproduction. This enzyme has been suggested to be involved in the host's bile acid balance, lipid metabolism and metabolic responses. Therefore, BSH has always been a research hotspot. Detailed knowledge of BSH structure and substrate preferences is a solid foundation for the development of BSH related products. This review explains the source and distribution of BSH, test method for BSH activity. It also introduces enzymatic properties and genetic organization. Finally, the potential applications of BSH research are briefly discussed. This review would provide theoretical basis for the in-depth research of BSH, developments of related functional foods, and other industry applications.

The effects of different processing methods on the quality of cooked crayfish during refrigerated storage were studied. Crayfish were treated with post-cooking sterilization (100 ℃, 5 min after 121 ℃, 5 min, 0.18 MPa) and simultaneous curing and sterilization (110 ℃, 10 min, 0.13 MPa), and no sterilization after cooking (100 °C for 5 min) samples were the control group. The three groups of samples were placed in a refrigerator at 4 °C, and the pH value, texture profile analysis (TPA), total volatile base nitrogen (TVB-N), thiobarbituric acid reactive substances (TBARS), centrifugal loss rate, myofibrillar protein characteristics, the total number of colonies of each group of samples were measured during this period, and combined with the observation of the microstructure, to evaluate quality changes in crayfish with different processing methods during refrigerated storage. The results showed that the muscle of crayfish was seriously broken under the treatment of first cooked and then sterilized, and the hardness and elasticity were significantly lower than those of other groups (P

In order to establish a rapid method for detecting the content of nitrite in food, green carbon quantum dots (CQDs) originating from chicken paw skin were synthesized by the one-step hydrothermal method. The morphology, structure and optical properties of CQDs were characterized systematically by high resolution transmission electron microscopy (HRTEM), UV-Vis absorption spectroscopy (UV-Vis), Fourier transforms infrared spectroscopy (FTIR), X-ray photoelectron spectroscopy (XPS) and fluorescence spectroscopy (FS) technologies. The prepared CQDs were distributed uniformly with a regular size, and the surface of the CQDs was rich in functional groups including hydroxyl, carboxyl, and carbonyl, et al. In addition, the CQDs emitted intense blue fluorescence under the excitation of a 365 nm UV light lamp. And the excitation spectrum and emission spectrum of CQDs were narrow and symmetrical, indicating CQDs had good luminescence properties. In the presence of Fe3+, the fluorescence of CQDs was quenched due to the formation of coordination bonds between Fe3+ and the oxygen-containing functional groups on the surface of CQDs. Based on that, a simple fluorescent probe was designed to detect indirectly nitrite (NO2−) by CQDs for nitrite possesses strong oxidation in acidic solution and was capable to transform iron (II) into iron (III) ions. The parameters including the excitation wavelength of CQDs, buffer pH value and reaction time were studied. Under the optimized conditions, the fluorescence quenching intensity of CQDs-Fe2+ fluorescent probe increased linearly with the NO2− concentration in the range of 1~500 μmol/L (R2=0.9979) with a low detection limit of 0.61 μmol/L, and the probe had a good anti-interference ability. The method was applied to the determination of NO2− in three marinate meat and satisfactory recoveries of 98.61%~100.95% and consistent data compared with ion chromatography were obtained. The results indicated that the CQDs-Fe2+ fluorescent probe could be used for the detection of NO2− in real samples. In summary, the fluorescent probe constructed based on the carbon dots of the biological matrix is green and safe, simple to prepare, can detect the content of nitrite in cured meat products, indicating a good practical application prospect.

Hyaluronic acid is a naturally occurring biopolymer possessing numerous functions within the body including wound repair, cell migration, and cell signaling. Due to its unique physical and chemical properties, it is widely used in health care products, cosmetics, and medicine.In 2021, hyaluronic acid is approved as a new resource food raw material in China, which has attracted widespread attention. Understanding its preparation, separation and purification methods is necessary to promote its industrial development.This article summarizes the physiological functions, preparation methods and preparation trends of HA from different sources, the effect of separation and purification method on HA purity, the application fields of hyaluronic acid, aiming to provide ideas for the development and comprehensive utilization of hyaluronic acid.

The study aimed to investigate the effect of carnosine combined with ultra-high pressure (CUH) on the lipid oxidation and myofibrillar protein (MP) of snakehead fish meat during refrigerated storage. Studies on lipid and protein oxidation, protein degradation and protein structure were used to analyze the effect of CUH treatment (carnosine concentration 25 mmol/L, ultra-high pressure pressure 300 MPa, pressure holding time 900 s) on snakehead fish. The lipid oxidation of fish meat was analyzed by measuring the lipoxygenase activity and the change of MDA content in CUH-treated fish. The change in the carbonyl content of MP during refrigerated storage was used to characterize the degree of fish protein oxidation. SDS-PAGE, TCA-soluble peptides and total protease activity were used to determine the effect of CUH treatment on fish protein degradation. In order to further understand the effect of CUH treatment on the structure of snakehead fish meat and MP during refrigerated storage, SEM and CD tracking measurements were carried out on fish. The results showed that the lipoxygenase activity of fish meat treated with ultra-high pressure decreased by 64.46%. The inhibition rates of lipid oxidation and protein oxidation of fish treated with CUH were 51.25% and 3.63% on the 9th day of the refrigerated storage period, respectively. The total protease activity of fish after UHP treatment decreased by 25.75%. CUH treatment significantly reduced the degradation of MP during refrigerated storage (P

Compare with the airborne and satellite-borne gravity measurements, terrestrial gravity measurements (TGMs) are closer to the sources of mass change and have relatively higher accuracy. The static anomalies and dynamic changes derived from TGMs have been widely used to study various geodynamic problems. Many high-precision gravity products using TGMs have become available since 21 century because of the development of modern observation techniques (especially those in absolute gravimetry) and the terrestrial network. Much of the progress of geodesy and geophysics has come from these products. In this paper, we briefly summarize the recent progress in geodesy and geophysics using high-precision TGMs during the last decade or so. The first group of applications adopts the gravity anomalies from TGMs, which includes constructing gravity field and geoid models, establishing crustal models, computing Moho undulations, and estimating the effective elastic thickness of the lithosphere. The second group of applications adopts the time-varying gravity changes from TGMs, which includes constructing time-varying gravity field models, detecting weak dynamic signals, estimating crustal tectonic deformation rates, and analyzing possible correlations with volcanic and seismic processes. We also discuss the next opportunities for ground gravimetry. Our findings could benefit the construction and development of the gravity observation system in the Chinese Mainland.