Excessive intake of fat in human body is the main cause of obesity and cardiovascular and cerebrovascular diseases. With the gradual enhancement of national health awareness, people gradually pay attention to fat substitutes with low calorie and low energy. Fat substitutes can not only meet people's sensory needs for color, fragrance and taste of food, but also reduce the intake of fat without changing the taste quality of food, which is of great significance to prevent various chronic diseases. Therefore, producing low-fat or fat-free food is an important way to improve people's eating habits and improve people's health. Fat substitutes are a kind of substances that mimic the fat in natural foods, which can be divided into 3 types: Fat substitutes (esterified derivatives of fatty acids, with almost zero digestibility in human body), fat simulators (carbohydrate fat simulators and protein fat simulators) and compound fat simulators. Fat substitutes can reduce the fat content in food, and more importantly, they can improve the oral sensory lubrication texture of food. This paper summarized the application and development prospect of fat substitutes in modern food research at home and abroad, in order to provide guidance for the research and development of low-calorie diet.

Objective To optimize the fermentation process with fresh Capsicum annuum L. as raw materials using Lactiplantibacillus plantarum L. and analyze the quality of fermented Capsicum annuum L. under the optimized conditions. Methods Using single factor and orthogonal experiments, the fermentation parameter of fermented Capsicum annuum L. inoculated with lactic acid bacteria were optimized and verified for the optimized fermentation condition. The changes of total acid, reducing sugar, nitrite content, and volatile substances were studied during the fermentation process of Capsicum annuum L. under the condition of the optimal parameters. By comparative analysis, the quality characteristics of strongly fermented Capsicum annuum L. were obtained. Results Under the condition of optimized fermentation parameters (fermentation temperature 35 ℃; fermentation time 10 d; lactic acid bacteria addition 4%; salt addition 4%), fermented Capsicum annuum L. showed sensory scores of 83.00±0.16, pH 3.38±0.02, total acid content of (15.55±0.24) g/kg, L^* of 36.76±0.82, a^* of 22.45±0.65, b^* of 4.04±0.43, and soluble solid substance of (13.07±0.03)%. Lactic acid and malic acid were the main organic acids of fermented Capsicum annuum L., and their contents were (1.9611±0.0800) mg/mL and (1.8600±0.1000) mg/mL, respectively. The flavor substances mainly included acids, esters, ketones, alcohols, and hydrocarbons. Among them, acids accounted for 65.45% of the relative content of total flavor substances. Conclusion Fermentation with lactic acid bacterium strain can enhance brightly fresh redness, crisp, rich aroma, suitable acidity, uniform texture and excellent taste, which are widely accepted by consumers.

Objective To optimize the extraction process of Chaenomeles sinensis polyphenols and study their antioxidant activity. Methods The extraction process of Chaenomeles sinensis polyphenols was optimized through single factor and orthogonal experiments; the in vitro experiments were simultaneously conducted to investigate the total reducing ability, 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical scavenging ability, and hydroxyl radical scavenging ability of Chaenomeles sinensis polyphenols. Results The optimal process for extracting polyphenols from Chaenomeles sinensis was: Ethanol volume fraction of 60%, solid-liquid ratio of 1:25 (g/mL), ultrasonic temperature of 55 ℃ and ultrasonic time of 90 min. Under these conditions, the polyphenol extraction amount was 2.22 mg/g; at a sample concentration of 1.0 mg/mL, the total reducing ability, DPPH radical scavenging rate and hydroxyl radical scavenging rate of Chaenomeles sinensis polyphenols were determined to be 2.41±0.02, 89.33%±0.24%, and 81.30%±1.27%, respectively, all higher than vitamin C at the same concentration (2.29±0.08, 86.05%±0.39%, 80.94%±0.41%), indicating that Chaenomeles sinensis polyphenols had good antioxidant activity and promising application prospects. Conclusion This study provides a reference for further research and application of polyphenols in Chaenomeles sinensis, offers new ideas for the diversified and high-value utilization of Chaenomeles sinensis resources, and provides theoretical basis for the deep processing of Chaenomeles sinensis resources and rational dietary selection.

Objective To establish a new method for simple identification of vitamin A (VA) and unsaturated fatty acids in natural cod liver oil. Methods The cod liver oil sample was saponified and injected into a high-performance liquid chromatography system to detect the content of VA. After saponification of cod liver oil and its excipients, injected them into a gas chromatography system to analyze the localization and percentage of linoleic acid, eicosapentaenoic acid (EPA), and docosahexaenoic acid (DHA), and distinguish fish oil from vegetable oil. Results Under the new method, the linear relationship of VA concentration was good within the range of 30.00-1500.00 IU/mL (r²=0.9999); the average recovery rate was 96.1%. The relative standard deviation of instrument precision was 0.18%, the relative standard deviation of method precision was 1.13%, and the relative standard deviation of intermediate precision was 0.98%. There was a significant difference in the content of fatty acids between vegetable oils, fish oil and cod liver oil. Cod liver oil and fish oil were rich in EPA and DHA, while linoleic acid was low. Corn oil, rapeseed oil and olive oil did not contain EPA and DHA, but they were rich in linoleic acid. Conclusion The detection method establish in this article is simple and accurate, and can be used for the determination of VA and unsaturated fatty acid content in cod liver oil, laying the foundation for the development of ideal quality standards.

Objective To elucidate the effects of flower of Changshan-huyou on the aroma profile of black tea. Methods This study employed solid phase microextraction-gas chromatography-tandem mass spectrometry (SPME-GC-MS) to differentially analyze the aroma components of flower of Changshan-huyou, Jiukeng black tea, and the derived Changshan-huyou scented tea. Results A total of 186 volatile compounds were identified in this paper, with 92, 78 and 67 kinds of volatile compounds detected in flower of Changshan-huyou, Jiukeng black tea and Changshan-huyou scented tea, respectively. The volatile composition of flower of Changshan-huyou was mainly characterised by alcohols and alkenes, whereas the volatile profiles of Jiukeng black tea and Changshan-huyou scented tea were mainly alcohol-rich. Nerolidol and linalool were found to be the predominant aroma components in Changshan-huyou scented tea, imparting a pronounced flora, fruity aroma and sweetness. Comparative analysis revealed an increase in alcohols and a concomitant decrease in alkenes in Changshan-huyou scented tea compared to flower of Changshan-huyou. Conversely, an increase in alkenes and a decrease in aldehydes were observed in Changshan-huyou scented tea compared to Jiukeng black tea. In addition, 32 kinds of unique compounds were identified in Changshan-huyou scented tea, which may be due to its unique processing techniques and the specific varieties of raw materials used. Conclusion The results of this research not only substantiate the aroma signature of Changshan-huyou scented tea, but also provide insights into its quality enhancement, paving the way for standardised production and innovative development strategies.

Objective To optimize the fermentation condition of Enterococcus faecium with the capability of high-yield biogenic amine production by response surface design. Methods Based on the previous single factor experiment results, response surface methodology was used to investigate the interaction among 3 factors with different levels, namely culture temperature (10, 15, 20 ℃), initial pH (5.0, 5.5, 6.0), and sodium chloride addition (4.5%, 5.5%, 6.5%), on the production of biogenic amines by Enterococcus faecium. The fermentation condition for controlling the production of tyramine and phenethylamine by Enterococcus faecium were optimized. Results The results showed that the regression equations for the production of tyramine and phenethylamine at 48 h were obtained with R²=0.9866, adjusted R²=0.9693 for tyramine and R²=0.9875, adjusted R²=0.9714 for phenethylamine, the order of affecting the production of casein and phenethylamine was culture temperature>NaCl addition>initial pH.. The optimal fermentation condition to control the tyramine production of Enterococcus faecium was initial pH of 6.0, incubation temperature of 10.9 ℃, and NaCl addition level of 4.5%. The optimal fermentation condition to control the phenylethylamine production was initial pH of 5.34, incubation temperature of 13.8 ℃, NaCl addition level of 5.8%. Conclusion The results provide references for the effective control of the biogenic amine production of Enterococcus faecium growing in fermented food such as fermented meat products.

In recent years, mycotoxin contamination in food has become an important food safety issue with global concern. Mycotoxins are a type of secondary metabolites produced by fungi with characteristics of high toxicity, difficult decomposition and chemical stability. It is of great significance to establish an efficient and safe mycotoxin detoxification technology applicable to food. Based onenzyme catalysis, the biological detoxification technology has the advantages of high substrate specificity, mild conditions, green environment, which can overcome the damage of traditional physical and chemical detoxification technology to the quality and nutritional value of food. Immobilized enzyme technology can improve the catalytic performance of enzymes, endow them with values such as stability, reusability, and high throughput, as well as overcome the limitations of biological enzymes in the application process. This article reviewed the application of immobilized enzyme technology in food mycotoxin removal, analyzed the deficiencies of the current immobilized enzyme technology applied in food detoxification and possible future research directions, with a view to providing research ideas for the construction of more efficient immobilized enzyme catalysts.

Objective To develop a Dioscorea polystachya-based probiotic beverage and assess its shelf life. Methods Using Dioscorea polystachya as the raw material, pH, viable cell count, and sensory evaluation were selected as indicators to screen suitable fermentation strains. The fermentation process was optimized through orthogonal experiments. The changes in viable cell count, sensory quality, soluble solids, pH, and total phenolic content of the beverage were studied during 30 days of storage at different temperatures (4, 25, 35 °C). A shelf life model was established based on the Arrhenius equation and first-order kinetic reaction, which was then used to predict the shelf life of the Dioscorea polystachya probiotic beverage. Results Lactobacillus plantarum, Streptococcus thermophilus and Lactobacillus bulgaricus were selected as the fermentation strains, with a ratio of 1:2:2. The optimal fermentation conditions were 4.5% sucrose, 4% inoculum, 48 hours fermentation time, and a fermentation temperature of 33 °C. The beverage stored at 4 °C showed better stability. The chemical kinetics model predicted the shelf life of the Dioscorea polystachya probiotic beverage to be 37 days under 4 °C storage conditions. Conclusion By optimizing the fermentation process and establishing a shelf life prediction model, this study provides theoretical and technical support for the production and storage of Dioscorea polystachya probiotic beverages, which can maintain good quality for an extended period under low-temperature storage conditions.

Objective To develop artificial hypoglycemic rice with leafy grass as a nutritional supplement, optimize its formula, and analyze its inhibitory activity on α-glucosidase and sensory quality. Methods The orthogonal experimental design was used to optimize the formula parameters of artificial rice, with corn amylose and rice starch as the main raw materials and edible leaf grass powder as the functional additive. The inhibitory activity of α-glucosidase was detected by enzyme labeling instrument to evaluate the hypoglycemic effect the samples, and the food sensory analysis was carried out according to the sensory evaluation method. Results The water extract of edible leaf grass showed a high inhibitory rate on α-glucosidase with an inhibitory concentration (IC₅₀) value 1.189 mg/mL, which was close to the inhibitory effect of the positive control acarbose. The optimized formula for producing artificial rice from edible leaf grass performed excellently in sensory evaluation, with good flavor, texture and appearance. Conclusion Edible leaf grass has excellent nutritional value and potential hypoglycemic activity. The artificial hypoglycemic rice develops based on it not only meets the special needs of diabetes patients, but also provides a new choice for the health food market, and has broad application prospects.

Objective To study the nutritional components of Weiying watermelon foranalyze and evaluate the nutritional quality of Weiying watermelon. Methods Namely “Meidu” watermelon from 2 main production areas of Weiying watermelon (S1 and S2) were used as experimental materials, and the same variety of watermelon from two other production areas (S3 and S4) as controls. The content of sugar, organic acid, amino acid, mineral, soluble solid, β-carotene, lycopene and vitamin C in the watermelons from the 4 production areas were detected and analyzed. Results The watermelon from different producing areas exhibited certain variations in quality characteristics. The sugar components in watermelon was mainly glucose and fructose, organic acids was mainly malic acid and lemon, free amino acids was mainly citrulline, and it also contains abundant mineral elements; the glucose content, sugar-acid ratio and sweetness-sourness ratio in S1 and S2 were higher than those in S3 and S4, while the total acid content was the opposite. In addition, the levels of the citrulline, β-carotene, lycopene and vitamin C in S1 and S2 were also higher than those in S3 and S4, respectively. The comprehensive performance of the nutritional quality of S1 and S2 were superior to that of S3 and S4 based on the principal component analysis. Conclusion Weiying watermelon has better flavor and texture, richer nutritional components, and superior nutritional quality.