Abstract:With the increasing pursuit of the high quality toward food, the importance of marine food ingredients in food industry was garnered great attention. Compared with terrestrial food ingredients, marine food ingredients come from a wide variety of sources with abundant diversity and unique functions, making them an important direction for food ingredient development. The categories and functions of marine food ingredients, including marine polysaccharides (alginate, chitin, etc.), marine proteins (phycobilin, collagen, etc.), marine lipids (glycerides, phopholipids, etc.) and functional small molecules (astaxanthin, fucoxanthin, etc.) were systematically summarized in this review. Additionally, the application of marine food ingredients in food quality and function improvement was introduced, covering the multiple processing fields of meat, diary and flour products. In view of the problems of limited types and lagging development of marine food ingredients, three future development trends were proposed, namely, green processing of marine food ingredients by biological manufacturing, personalized customization of marine food ingredients by precise manufacturing, and development of marine food ingredients by intelligent manufacturing. Through the systematic summary of the types, functions and applications of marine food ingredients, as well as the prospect of future development trend, it was expected to provide reference for the healthy and rapid development of food ingredients industry.

Abstract:Acrylamide is a typical food contaminant widely present in fried, baked, and other thermal processed foods. Dietary exposure to acrylamide is closely associated with the risk of diseases such as cardiovascular diseases and breast cancer. The International Agency for Research on Cancer has classified it as a Group 2A “probable human carcinogen”. Considering the potential harm and toxic threats of acrylamide posed to human health, it was crucial to optimize food formulations and develop new technologies to effectively control acrylamide levels in thermal processed foods and reduce human exposure. The research progress on acrylamide formation pathways during food heat processing, dietary exposure, metabolism in the body, health risks, and prevention and control measures were summarized. Acrylamide was primarily formed through the Maillard reaction under high-temperature conditions, especially in foods rich in reducing sugars and amino acids. Its content was significantly influenced by food composition and processing conditions. The main formation pathways of acrylamide were the asparagine pathway and the acrolein pathway.Acrylamide from food sources was closely related to health risks. Due to its complex metabolic pathways in the human body, it might cause neurotoxicity, reproductive toxicity, and genotoxicity and was potentially associated with cancer development. In the field of food science, preventive and control measures for acrylamide mainly focus on optimizing thermal processing techniques and adding exogenous food additives.By integrating raw material selection, process optimization, and the addition of exogenous substances, effective strategies for reducing acrylamide levels were explored and analyzes key directions for future research were analyzed in this study. The goal was to provide a scientific basis for inhibiting acrylamide formation during food processing, supporting the healthy development of the food industry, and ensuring consumer dietary safety.

Abstract:Per- and polyfluoroalkyl substances (PFASs) were a class of synthetic chemicals widely used in industrial products and consumer products. Due to their structural diversity and bioaccumulation properties, PFASs were recognized as highly concerned persistent pollutants. PFASs in food contact paper could contaminate food and endanger consumer health. There were various categories of PFASs, usually divided into polymers and non-polymers categories. Non-polymeric PFASs included perfluoroalkyl acids (PFAAs) and their precursors, while polymeric PFASs were mainly perfluoropolyethers (PFPEs) and fluoropolymers polymerized by multiple PFASs. According to the number of carbon atoms in the fluorine segment structure, PFASs were divided into long-chain PFASs with more than 7 carbon atoms and short-chain PFASs. Among them, common perfluorooctane sulfonic acid (PFOS) and perfluorooctanoic acid (PFOA) were long-chain PFAAs, which were the key substances in research and regulatory supervision. In food contact paper, PFASs came from a wide range of sources, which were not only intentionally added through impregnation, sizing, or coating to improve the performance of paper products but also unintentional addition caused by manufacturing process residues or external environmental pollution. Pollution was common in various types of paper products. Although some traditional PFASs were under control, new PFASs and their precursors were still being detected, and the degree of pollution in different countries and regions was affected by regulatory efforts. In terms of dietary exposure, PFASs in food contact paper could migrate to food and enter the human body through dietary intake. Migration was affected by temperature, time, and food properties. The risks of using fast food paper at high temperatures should be closely monitored.Many countries and regions have implemented controls on PFASs, with different limit requirements. China also prohibited the production, processing, and use of some PFASs and adopted forward inventory management. Detection technologies included quantitative analysis of targeted PFASs, fluorine content screening, and non-targeted analysis of unknown PFASs. In the future, research on PFASs in food contact paper should focus on comprehensive assessment, combining multiple analytical methods, and tracing the source, distribution and toxicity hazards of unknown PFASs to improve regulatory regulations.

Abstract:Chiral compounds play an important role in flavor research, among which 3-methyl-γ-lactones with two chiral centers are a key class of spices, mainly used to prepare peach, coconut, vanilla and other flavors. Because of its water solubility, it is also widely used in alcohols and beverages as a food additive. The previous synthetic methods often had defects such as difficult acquisition of starting materials, complicated operation, and poor versatility. The process involved obtaining optically active trans-3-methyl-octanolide, nonanolide, and decanolactone was explored. (E)-3-alkenoic acids starting from the corresponding aliphatic aldehydes and malonic acid were synthesized through Knoevenagel condensation. Subsequently, their methyl esters underwent Sharpless asymmetric dihydroxylation to introduce chiral centers, followed by elimination and conjugate addition steps to yield the desired target compounds. The final structures of all products were confirmed by NMR and GC-MS, and the enantiomeric excess (ee) values of the final products were determined by chiral GC. The enantiomeric excess (ee) values for (3R,4S)-trans-3-methyl-γ-octanolides and (3S,4R)-trans-3-methyl-γ-octanolides were 84% and 92%, respectively. For (3R,4S)-trans-3-methyl-γ-nonanolides and (3S,4R)-trans-3-methyl-γ-nonanolides, the ee values were 87% and 95%, and for (3R,4S)-trans-3-methyl-γ-decanolides and (3S,4R)-trans-3-methyl-γ-decanolides, the values were 83% and 96%. Notably, each enantiomer exhibited distinct odor characteristics. All presented different degrees of coconut aroma, sweet aroma, and burnt aroma. The aroma characteristics of the enantiomers of the three lactone trans-configuration products prepared in this paper all showed significant differences.

Abstract:The aim of the present study was to investigate the effects of fructo-oligosaccharides (FOS), galacto-oligosaccharide (GOS), and the mixture of FOS and GOS (FOS+GOS) on the proliferation of splenic lymphocytes, as well as the regulation of Th cell differentiation and Th1/Th2 balance. Spleen lymphocytes of mice were incubated with FOS. GOS and FOS+GOS mixture, respectively, with or without Concanavalin A (ConA) stimulation. Spleen lymphocyte proliferation level wasdetected by MTT colorimetric assay. To explore the differentiation direction of Th cell, the expression ofThl and Th2 cytokines and the transcription factors T-bet and GATA-3 were determined by enzyme linked immunosorbent assay (ELISA) and PCR, respectively. The results showed that the proliferative activities of FOS, GOS and FOS+GOS mixture on mouse splenic lymphocytes were concentration-dependent, and all of them exhibited promoting splenic cell proliferation activity at the concentration of 125μg/mL, with FOS+GOS mixture having the strongest promotion effect on splenic cell proliferation. There was no significant difference among them on the splenic cell proliferation activity under ConA stimulation. FOS+GOS mixture had the strongest effect on the splenic cell proliferation activity without ConA stimulation. The supplementation of GOS and FOS+GOS mixture increased the secretion of Th1-type cytokine IFN-γ and the mRNA expression levels of IFN-γ and IL-2, and inhibited the expression and secretion levels of Th2-type cytokine-related mRNA including IL-4 and IL-5. In conclusion, both FOS+GOS mixture and GOS possess immunoregulatory activity and regulate Th1/Th2 balance, which deserve them as potential anti-allergic ingredients.

Abstract:Numerous studies have proven that fungal polysaccharides have anti-aging potential. However, the biological mechanisms of anti-aging of fungal polysaccharides have not been fully elucidated. Poria cocos is a traditional medicinal and dietary fungal resource in China and its main active component is polysaccharides. The effects of Poria cocos-derived polysaccharides (carboxymethylpachymaran, CMP) on the immune functions and plasma lipid in 12-month-old mice were measured after oral gavage with a dosage of 50mg/kg per day CMP for a consecutive 30d, and then the proteome profiles in the small intestinal tissues from the aged mice were evaluated using proteomic method based on isobaric tags for relative and absolute quantification (iTRAQ) to explore the anti-aging potential of CMP and the underlying mechanisms. The results showed that CMP increased thymic index, enhanced the activities of splenic lymphocyte proliferation and natural killer (NK) cells, elevated the levels of serum IL-6 and IL-10, decreased the levels of serum total cholesterol (TC), triglyceride (TG),and low-density lipoprotein-cholesterol (LDL-C), but increased high-density lipoprotein-cholesterol (HDL-C) levels in the aged mice, indicating that CMP partially restored the age-related immune function decline and altered plasma lipid profiles. Meanwhile, under the action of CMP, a total of 67 differentially regulated proteins (DRPs) were identified in the small intestinal tissues, of which 41 proteins were down-regulated and 26 proteins were up-regulated in expression. Bioinformatic analysis elucidated that these DRPs induced by CMP were mainly involved in the biological functions of ribosome component, protein synthesis, regulation of immune function, and lipid and energy metabolism. Protein-protein interaction analysis revealed that these DRPs induced by CMP had direct and/or indirect interactions. Among them, nine DRPs, including heat shock protein HSP 90-beta and HSP 90-alpha, 60S ribosomal protein L4, L7, L6 and L19,40S ribosomal protein S10, and heterogeneous nuclear ribonucleoprotein A/B and A1, were the key proteins by calculating the degree of edges in response to the actions of CMP to enhance immune function and plasma lipid in aged mice. These findings might provide a basis for the applications of CMP in anti-aging foods and deepen the understanding of the biological mechanism of anti-aging of fungal polysaccharides in terms of immune functions and blood lipid profiles.

Abstract:Using polysaccharides from Leccinum crocipodium (Letellier.) Watliag (LCP) as raw materials, the digestion and fermentation characteristics of LCP were investigated by simulating human gastrointestinal digestion and colonic fermentation, combined with high performance gel permeation chromatography, high performance liquid chromatography, gas chromatography-mass spectrometry and 16S rRNA high-throughput sequencing analysis. The results showed that there was no sigificantly change of molecular weight, free monosaccharides, and reducing sugar content of LCP after digestion in simulated oral cavity, stomach, and small intestine. LCP could maintain stability in the above digestive tract. When LCP was fermented in simulating colonic fermentation, the pH value, and molecular weight of LCP gradually decreased, the signal of monosaccharide response gradually disappeared, while the content of lactic acid and short chain fatty acids gradually increased in fermentation system. Moreover, the carbohydrate utilization rate reached 85.94%±0.99%, the content of propionic acid and butyric acid increased to (15.06±0.16) mmol/g and (4.70±0.08) mmol/g, respectively, after 36h of fermentation. In addition, high throughput sequencing analysis of 16S rRNA showed that LCP could increase the abundance of Bacteroidetes and reduce the ratio of Firmicutes to Bacteroidetes (F/B). Bacteroidetes was the main dominant bacterium in the fermentation process of LCP, playing an important role in the fermentation process of LCP. In summary, LCP was difficult to be digested by simulated gastrointestinal tract, but could be utilized through gut microbiota, to increase the content of short chain fatty acids and regulate the composition of gut microbiota. LCP would be expected to develop as a functional substance to improve human intestinal health in the future.

Abstract:In order to study the effects of gallic acid (GA) on muscle quality and myoglobin conformation of bluefin tuna during refrigerated storage (4℃), different concentrations of GA (200mg/kg and 400mg/kg) were used to treat bluefin tuna and analyzed the changes in its quality characteristics. The effects of GA on the structure and microenvironment of myoglobin were further investigated by multispectral technique. The binding sites of the two proteins were determined by molecular docking. Results showed that during storage at 4℃, the quality characteristics of tuna meat exhibited varying degrees of deterioration, including a noticeable browning effect and a decrease in redness value. Compared with GA treatment group, lipid oxidation, metmyoglobin relative content, total volatile basic nitrogen and the total number of colonies in control group showed a significant upward trend. Additionally, there was a decrease in bound water content and an observed migration of water. Furthermore, varying degrees of muscle fiber bundle disruption were also noted. In conclusion, low concentration (200mg/kg) of GA could effectively alleviate the deterioration of quality of bluefin tuna. By multispectral analysis, low concentration of GA could stabilize the secondary structure of myoglobin well and had fluorescence quenching effect on myoglobin. Molecular docking results showed that myoglobin formed hydrogen bonds with GA through Leu 42, Pro 44 and His 42. This experiment provided basis and strategy for improving the quality of thawed bluefin tuna.

Abstract:Low-voltage electrostatic field technology is a technique that can prolong the shelf life of fruits and vegetables. To explore its impact on the postharvest quality of fruits and vegetables, the effects of low-voltage electrostatic field (200mV and 300mV) treatment on the quality, reactive oxygen metabolism and mitochondrial redox metabolism of cherry tomatoes during storage at (4±1)℃ were investigated using cherry tomatoes as materials. The results showed that compared with the control group, the low-voltage electrostatic field treatment reduced the respiration rate, delayed the increase of weight loss rate and the decrease of soluble solids and acidity, and maintained the hardness of cherry tomatoes. At the same time, the low-voltage electrostatic field treatment significantly increased the activities of peroxidase, catalase, and superoxide dismutase as well as the content of ascorbic acid in cherry tomatoes during storage (P<0.05), and in turn inhibited the production and accumulation of reactive oxygen species, such as hydrogen peroxide and superoxide radical. Further analysis revealed that low-voltage electrostatic field treatment also inhibited the decrease of mitochondrial cytochrome c/a and increased nitric oxide content in cherry tomatoes to maintain the mitochondrial redox state. Meanwhile, it increased mitochondrial NAD⁺ content and decreased NADH content, increased the NAD⁺/NADH ratio, and kept the mitochondrial redox potential at a high level. Low-voltage electrostatic field treatment could inhibit the generation of reactive oxygen species and maintain the balance of mitochondrial redox state in cherry tomatoes, thus maintaining their storage quality.

Abstract:Chitosan, sodium alginate, sodium alginate/gelatin and sodium alginate/carboxymethyl cellulose were used as immobilization carrier materials to investigate the immobilization methods of β-galactosidase, and the synthesis of galacto-oligosaccharides (GOS) by the suitable immobilized enzyme was studied. The results showed that the obtained suitable immobilization carrier was chitosan, and the optimal immobilization conditions for β-galactosidase were chitosan mass concentration of 0.03g/mL, standing time of 2h, glutaraldehyde volume fraction of 2%, crosslinking time of 3h, adsorption time of 12h, immobilization temperature of 60℃, enzyme dosage of 0.4mg/g (based on the mass of chitosan microspheres). Compared with the free enzymes, the stability of immobilized enzymes against acid, alkali and heat was significantly improved. Chitosan immobilized β-galactosidase was further used to synthesize GOS, and the optimal reaction conditions were determined as follows:amount enzyme of 2U/mL, pH of 6.0, reaction temperature of 50℃, initial lactose mass concentration of 500g/L, and reaction time of 14h. Under these conditions, the GOS yield reached 52.61%, which was higher than those reported GOS yield (25.1%~46.0%). And the content of GOS with polymerization degree greater than or equal to 3 in the product was 37.07%. After repeated use of the immobilized enzyme for five times, the GOS production activity remained 97.21%. The chitosan-immobilized β-galactosidase obtained from the study had a promising application in the field of GOS synthesis.

Abstract:D-allulose is a novel functional sugar substitute primarily produced from the high-cost substrate D-fructose, using D-allulose 3-epimerase to achieve the conversion. Identifying low-cost raw material alternatives to D-fructose for D-allulose production is crucial for its industrialization. In this study, glucose isomerase and D-allulose 3-epimerase were linked with either flexible or rigid peptide linkers in different sequential orientations, constructing four configurations of fusion proteins. The fusion protein configuration, exhibiting the best catalytic performance, was selected and optimized to catalyze D-allulose from the lower-cost substrate D-glucose. The results showed that fusion proteins AE3G and AS3G possessed both glucose isomerase and D-allulose 3-epimerase activities, converting D-glucose to D-fructose and D-allulose. AE3G, connected with a rigid peptide linker, demonstrated higher activity than AS3G, which connected with a flexible linker. The optimized catalytic conditions for AE3G were temperature of 65℃, Tris-HCl buffer of 50mmol/L, pH of 7.5, Co²⁺ concentration of 0.5mmol/L, Mn²⁺ concentration of 0.5mmol/L, and wet cell concentration of 75g/L. Under these conditions, using 100g/L D-glucose or volume fraction 5% F55 high-fructose corn syrup as substrates, the fusion protein produced 17.2g/L and 12.5g/L D-allulose, respectively, with a mass ratio of D-glucose, D-fructose, and D-allulose in the reaction mixture of 2.5∶2.3∶1.0. This study aimed to verify the feasibility of using fusion proteins to catalyze the conversion of D-glucose to D-allulose, and the results indicated that the equilibrium concentration of D-allulose was higher than reported values, providing a theoretical basis for low-cost D-allulose production.

Abstract:In order to study the aroma differences of coffee liquid at different extraction temperatures and the correlation between sensory evaluation and aroma compounds, this study used three types of commercial cold brew coffee and three types of commercial hot brew coffee were used as samples and aroma sensory evaluation was conducted using the check-all-that-apply method based on emoticons. At the same time, the aroma components of the coffee extract were determined using headspace solid-phase microextraction-gas chromatography-mass spectrometry, and the differences in volatile components between cold brew and hot brew coffee were analyzed. The research results showed that a total of 93 volatile components were identified in 6 different coffee extracts, and most of the volatile compounds in cold brew coffee were higher than those in hot brew coffee. In terms of aroma sensory evaluation, the overall preference score of cold brew coffee was higher than that of hot brew coffee. The panelists mainly chose positive emoticons to describe cold brew coffee, while choosing negative emoticons to describe hot brew coffee. Pyrazines, furans, aldehydes, acids, esters, ketones, and alcohol compounds endowed cold brew coffee with a stronger nutty, caramel, sweet, and floral aromas, making it more flavorful. The pyridine, pyrrole, and phenolic compounds in hot brew coffee made it more inclined towards woody, grain, and roasted aromas, with a certain smoky and spicy taste. This study provided data reference for exploring the aroma quality of cold brew and hot brew coffee,and hoped to provide theoretical basis for the research,development, improvement, and application of cold brew and hot brew coffee.

Abstract:Chinese traditional fruit wood roast chicken dishes were used as research object, to analyze the flavor fingerprint of Chinese traditional roast chicken dishes, and to clarify the contribution of spices to roast chicken flavor by solvent-assisted flavor evaporation-gas chromatography-olfactometry-mass spectrometry. The results showed that a total of 73 volatile flavor compounds were identified in roast chicken, among which 29 were key flavor compounds. According to the analysis of odor activity value and flavor dilution, anisaldehyde and anethole from fennel had a significant effect on the flavor of roast chicken, which gave anise-like aroma to roast chicken. Partial least squares discrimination analysis showed that 12 volatile flavor compounds, including 1-hydroxy-2-propanone, anisaldehyde, anethole, methyl eugenol, ethyl acetate, eugenol, ethylpyrazine, myristicin, butyl acetate, α-phellandrene, benzaldehyde, and γ-terpinene, were important variables that affected the aroma differences of roast chicken.Addition of spices changed the types and contents of volatile flavor compounds, as well as the balance and interaction between them, giving roast chicken unique aroma characteristics. The purpose of the study was to provide data support for the control of flavor, optimization of new technology, as well as the development of special spices for Chinese traditional roast chicken prepared dishes.

Abstract:Flaxseed, as a functional food raw material, was rich in α-linolenic acid, high-quality proteins, soluble polysaccharides, lignans and other active lipid concomitants, thereby possessing high nutritional value and potential for development and utilization. To explore the effect of different thermal sterilization conditions (65℃-30min, 85℃-15min and 95℃-15s) on the physicochemical stability of flaxseed milk, with a focus on the changes in interfacial properties of oil bodies in system, flaxseed milk was used as the research object. The results showed that the thermal sterilization treatment resulted in an increase in the mean particle size of flaxseed milk by 95.58%(P<0.05) and a decrease in the absolute value of the Zeta potential by 12.26%(P<0.05), which was accompanied by the weakening of viscoelasticity and an improvement of physical stability of the milk. After thermal sterilization, the mass ratio of protein at the oil bodies interface in flaxseed milk increased by 64.42%(P<0.05) and the mass ratio of total sugar increased by 97.95%(P<0.05). The cryo-scanning electron microscopy imaging further confirmed the adsorption of exogenous storage proteins and soluble polysaccharides at the interface of oil bodies. In addition, the thermal sterilization treatment increased the total phenolic content of the oil bodies interface in flaxseed milk by 1.42 times(P<0.05), the flavonoid content by 4.94 times(P<0.05), the free radical scavenging capacity of DPPH by 4.64 times(P<0.05), and FRAP ferric reducing antioxidant ability by 54.05%(P<0.05). Suitable thermal sterilization treatment (85℃-15min) could enhance the physical and chemical stability of flaxseed milk based on the interfacial composition structure remodeling of oil bodies, which was hoped to provide a theoretical basis for further broadening the intake forms of the whole components of flaxseed, and their application in fruit and vegetable juices, and dairy beverage.

Abstract:Cassava starch was used as raw material to prepare sour cassava starch (SCS) by lactobacillus fermentation. The effect of different drying technologies including hot air drying (HA), heat pump drying (HP), vacuum freeze drying (VF), spray drying (SD), sun-drying (S) on the quality characteristics and particle structure of SCS was investigated. The results showed that SCS dried by HA and HP had higher yield, better color, lower moisture content, lower gel hardness and lower gumminess. The SCS particles surface were rough, closely arranged and unevenly distributed, and with obvious curl and wrinkle. The SCS dried by VF had the highest yield and the lowest moisture content. It could retain nutrients better and had the best color. The particles were loose and uniform distribution, and some particles surface were collapsed and folded. The SCS dried by SD had the lowest yield, fat content, protein content, acidity, gel springiness and cohesiveness, whereas it had the highest ash content, L* value and pH value. The particles were serious aggregation and nonuniform in distribution, and the round depressions and folds occurred on the surface. The SCS dried by S had the highest moisture content, amylose content, a* value, b* value, whiteness index, gel texture properties (hardness, gumminess, springiness and cohesiveness) and comprehensive scores, whereas it had the lowest ash content, total starch content, amylopectin content and L* value. The particles were uniformly distributed and some complete particles were observed. In summary, the best quality characteristics and particle structure of SCS products could be obtained by S, because of the mild dry conditions and then followed by SCS products obtained by VF. The results of this study provided theoretical basis and technical reference for industrial drying, processing and utilization of SCS.

Abstract:The incidence rate of hyperuricemia is increasing worldwide. Uric acid reducing lactic acid bacteria (LAB) could be the new way for the prevention and auxiliary treatment of hyperuricemia. To investigate the underlying mechanism of LAB in reducing uric acid, 20 strains of LAB were selected as the research objects. High performance liquid chromatography(HPLC) was used to screen LAB with the ability to reduce uric acid and the mechanism was explored by determining the active composition of LAB. The results showed that Lacticaseibacillus rhamnosus N1-2, Lacticaseibacillus rhamnosus N1-5,Lactobacillus helveticus LH3, Lactobacillus helveticus T1(1)-1 and Lacticaseibacillus paracasei LP4 exhibited strong hypouricemic activity(41.96%, 42.50%, 44.18%, 46.22% and 37.33%, respectively) in vitro. By studying the components of 5 strains of lactobacillus and exploring their mechanism of UA-lowering, it was found that, the uric acid lowering effect of live bacteria was significantly higher than that of dead bacteria(P<0.05), but the uric acid lowering effect of live bacteria cell lysates and dead bacteria cell lysates was similar and was higher than the whole live bacteria(P<0.05). Furthermore, the uric acid lowering effect of 5 strains of lactobacillus was not related to the cell wall, extracellular secretions, and other components in cell lysate. The uric acid lowering effect was also unrelated to the activity of intracellular uricase, which was widely believed to play a key role in most studies. Through the protoplast adsorption experiment and the scanning electron microscope experiment after the protoplast adsorption of uric acid, the 5 lactobacillus strains showed a close relationship between the reduction of uric acid and the cell membrane. The study aimed to provide a theoretical basis for the screening and application of LAB for reducing urine.