Objective To explore the factors affecting protease activity in raw milk. Methods Used raw milk and milk samples before and after different processing techniques as samples, acid, alkali and neutral protease activities were determined based on the Folin phenol method. The effects of different regions, seasons, ranch temperatures, somatic cell numbers, number of psychrophilic bacteria, and behavioral stress on protease activity in milk samples were analyzed at the ranch and process levels, and the effects of different processing techniques on product protease activity were analyzed. Results The contribution rate of protease activity changes at the ranch level was in the following order: Season (resulting in temperature changes)>highest temperature on the ranch>region>number of psychrophilic bacteria>number of somatic cells. In the comparison of protease inactivation rates under different treatment processes, the 4 treatment processes had the following order of protease inactivation rate: Ultra-high temperature treated (UHT) preheating treatment (90 ℃, 5 s)>pre heat treatment before sterilization (70 ℃, 5 s)>reverse osmosis (RO)>centrifugal sterilization. Conclusion The main influencing factor at the ranch level is the seasonal temperature changes that affect protease activity, simultaneously using preheating treatment before sterilization at the process level can achieve a protease inactivation rate of over 50%.

Objective To study the effect of n-3 polyunsaturated phosphatidylserine on the anti-apoptotic ability of rat hippocampal neuron cells (RHNC). Methods An apoptosis model using RHNC as the target and phorbol acetate (PMA) as the inducer was established. Using docosahexaenoic acid (DHA)/eicosapentaenoic acid (EPA) phosphatidylserine (DHA/EPA-PS) as a protective agent, the morphology of cells at different stages of apoptosis was observed under a laser confocal microscope after staining with acridine orange. The effect of n-3 polyunsaturated phosphatidylserine, represented by DHA/EPA-PS, on the anti-apoptotic ability of RHNC was studied at the cellular level through the Annexin V-FITC/PI double staining experiment. Results An RHNC apoptosis model with a PMA concentration of 10.0 mg/L and an action time of 24 hours was established. The 15.0 mg/L DHA/EPA-PS showed the best cell pre protection effect, with an apoptosis rate of 11.46%±4.11%. Early and mid-stage apoptotic cells were fewer and did not produce late stage apoptotic cells. Cells pre protected with 15 mg/L DHA/EPA-PS exhibited intact morphology and nuclear membrane, and their protrusions were not affected by PMA. Conclusion n-3 polyunsaturated phosphatidylserine, represented by DHA/EPA-PS, has certain anti-apoptotic ability against RHNC. The study provides good data support for future research on the biological activity of phosphatidylserine.

In the economic shellfish farming on coastal mudflats in China, the Sinovovacula constricta occupies an important position. In recent years, due to the rapid urbanization and industrialization in China, marine pollution has threatened the living environment of Sinovovacula constricta. Polluted Sinovovacula constricta can accumulate toxins in their bodies, which can be transmitted through the food chain and ultimately endanger human health. Therefore, the food safety issue of Sinovovacula constricta has received widespread attention. With the continuous improvement of the transportation network and the gradual maturity of the live-keeping technology system, more and more Sinovovacula constricta are being sent to inland areas, expanding the consumer market. Therefore, Sinovovacula constricta must undergo purification treatment before entering the circulation process. As consumers' demands for the taste and quality of fresh Sinovovacula constricta continue to increase, the purification and live-keeping processes of Sinovovacula constricta have become particularly important. This article reviewed the current research progress in the purification methods of Sinovovacula constricta in China, the advantages and limitations of different purification processes, the influences of environmental parameters on purification, and live-keeping technologies, providing a reference for in-depth research on the purification and live-keeping technologies of Sinovovacula constricta.

Objective To analyze the nutritional components of traditional sour whey and its products and explore its comprehensive utilization value. Methods The traditional sour whey was separated step by step into a variety of homogeneous and stable whey products by composite membrane separation technology. The content of protein, fat, peptide, mineral and lactose was used as evaluation index to analyze the nutritional characteristics and availability direction of these products. Results Four kinds of whey products: Thin cream RQ-1 for milk standardization (fat content 47.4 g/100 g); microfiltration membrane interception liquid RQ-3 was a high-protein and polypeptide drink (protein content 3.52 g/100 g; peptide content 0.92 g/100 g); ultrafiltration membrane interception liquid RQ-5 was a pure peptide type drink (peptide content 0.87 g/100 g); the reverse osmosis membrane interception liquid RQ-9 could be used for the development of mineral drinks (ash content 0.88 g/100 g, 5 major elements detected) and the recycling of lactose (lactose content 3.92 g/100 g). Conclusion “Turning waste into treasure” of traditional sour whey is directly related to the increase of herdsmen's income. The membrane separation method provides a new solution for its comprehensive utilization.

Starch as an important component of edible films, has many advantages such as safety, degradability, low cost, and wide availability. Chitosan is widely used in food packaging films due to its good biodegradability, antioxidant, antibacterial, and good film-forming properties. The application of chitosan in starch based edible films and the development of packaging materials with good biodegradability and safety is a research hotspot in the food packaging industry. This paper reviewed the structure, film-forming properties, and biological activity of chitosan, and elucidated the film-forming mechanism of chitosan starch based edible films and the film-forming properties of chitosan in different types of starch matrices, discussed the application of chitosan-starch composite edible film in meat, fruits, vegetables, and other foods. With the deepening of research, chitosan starch based edible packaging film has broad development prospects in the future. This paper provides a basis and direction for the application of chitosan in starch based edible film, and provides a good theoretical basis for its application in new food packaging.

Supercritical carbon dioxide extraction technology, as a unique, clean, efficient, and energy-saving separation method, can solve many defects in traditional extraction techniques such as the use of toxic organic reagents, high energy consumption, and low extraction yield. Therefore, it has good application prospects in food processing. As one of the 3 kinds of major nutrients of human body, oil not only maintains the normal physiological function of human body, but also has many beneficial physiological functions, which is of great value to improve human health and prevent diseases. Therefore, this article focused on supercritical carbon dioxide extraction technology, systematically summarized supercritical carbon dioxide extraction's concept, mechanism, process flow, characteristics and influencing factors, as well as the research status in recent years regarding its application in plant oils such as wheat germ oil, rice bran oil, and soybean germ oil, as well as animal fats like fish oil and insect oil, aimed to provide a theoretical reference for the scientific research and food processing applications of supercritical carbon dioxide extraction technology.

In recent years, with the increasing emphasis on health and the increasing awareness of environmental protection, people have gradually explored and put forward more stringent and comprehensive requirements in the analysis of the total amount and form of elements in food and medicine. Although traditional extraction methods can meet the needs of analysis to a certain extent, they often accompanied by various problems. Therefore, exploring more green, efficient and environmentally friendly element extraction technology has become an important thing. As a biocatalyst, enzyme has attracted increasing attention in the field of element extraction because of its unique advantages, such as high specificity, mild reaction conditions and environmental friendliness. Enzymatic extraction is a method that using the biochemical action of enzymes to destroy the structure of the sample and breaking the macromolecules into amino acids, so as to extract metal elements. This paper reviewed the application of enzymes in the extraction of elements in cereal foods, vegetables, traditional Chinese medicine, seafood and feed, and discussed which enzymes are suitable for different matrices, the advantages and disadvantages of enzymatic extraction methods, so as to better understand the compatibility of enzymes with different samples. It provides a reference for the future use of enzymatic extraction in the total amount and form of elements in different substances.

Objective To establish a method for the simultaneous detection of hypoxanthine, guanine, xanthine, and adenine in edible fungi by high performance liquid chromatography, and use this method to the analysis of commercially available edible fungi. Methods The purines (hypoxanthine, guanine, xanthine, and adenine) from edible fungi were extracted by using acid hydrolysis. The chromatographic column was selected based on the resolution and peak shape of the 4 kinds of purines. Detection conditions, including the mobile phase ratio, flow rate, column temperature, and injection volume, were optimized, and the methodology was validated. Results The results showed that using Insert Sustain AQ-C₁₈ column with a mobile phase consisting of 50 mmol/L ammonium acetate solution (pH 4.0) and methanol (V:V=97:3), at a flow rate of 0.6 mL/min and the column temperature of 30 ℃, with an injection volume of 10 μL and detected at 254 nm, the 4 kinds of purines could be completely separated with good peak shapes. And the methodological validation results showed that this method exhibited a good linear relationship within the detected range. Conclusion A high performance liquid chromatography method is established through the optimization of detection conditions, which effectively differentiates and simultaneously detects the 4 kinds of purines in edible fungi. The content of hypoxanthine and xanthine (uric acid precursor substances) are very low or undetectable in the detected edible fungi. Based on the purine intake guidelines in the Encyclopedia of Chinese nutritional science, the dietary intake of the currently available commercial edible mushrooms is determined.

In recent years, bioactive peptides with potential edible values have received widespread attention as consumer demand for functional foods grows. The bioactive peptides in fermented soybean foods (FSF) have attracted much attention because of their safe and non-toxic properties. Nowadays, a large number of FSF peptides have been identified through isolation and purification, which not only contain rich nutritional value, but also have a variety of physiological activities such as hypoglycemia, hypotension, antioxidant and antimicrobial activities, and have a good prospect for development in the field of food and health care products. This paper systematically classified and analyzed the biological activities of the active peptides in FSF in the light of the research progress of FSF in recent years, summarized the separation and purification methods of FSF peptides, and summarized the hypoglycemic mechanism of the active peptides in FSF, in order to provide ideas for the deeper study of FSF, and to provide theoretical foundations and support for the production of FSF active peptides and their development and application in the field of functional foods in the future.

Objective To investigate the differences in amino acid content and nutritional value of Elaeagnus angustifolia from different regions in Xinjiang. Methods The amino acid content in the pulp of 18 Elaeagnus angustifolia samples from 9 different counties in Xinjiang were evaluated by automatic amino acid analyzer at wavelengths of 570 nm and 440 nm by post-column derivative ion exchange chromatography, and by comparing with Food and Agriculture Organization of the United Nations/World Health Organization (FAO/WHO) amino acid pattern spectrum and ideal protein standard, the amino acid ratio (RAA), ratio coefficient of amino acid (RC) and score of ratio coefficient (SRC) were calculated. The nutritional value of amino acids in the pulp of Elaeagnus angustifolia was evaluated. Results There were 17 kinds of amino acids in the pulp of 18 Elaeagnus angustifolia samples. The essential amino acids accounted for 13.87%-21.96%, and the pharmacodynamic amino acids accounted for 73.03%-80.21%. The amino acid composition of Elaeagnus angustifolia were quite different among regions, and the content of total amino acids, essential amino acids and pharmacodynamic amino acids were all the highest in Qira Country, with values of 3.69, 2.73, and 0.81 g/100 g, respectively. According to the comparison of FAO/WHO amino acid pattern spectrum and whole egg reference standard, Elaeagnus angustifolia in Yen gisar County had the highest SRC of 66.92% and 72.27%, respectively. Conclusion As a plant-based food source, Elaeagnus angustifolia pulp is rich in amino acids and has high medicinal value. The amino acid content of them sold in different regions of Xinjiang is different, so the subsequent study can further explore the breeding and processing of the dominant varieties of Elaeagnus angustifolia.