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To investigate the water-binding mechanism of fresh sweet potato residue, the water distribution in starch processing residues from 10 varieties of sweet potato was determined by low-field nuclear magnetic resonance (LF-NMR), and the correlation between water states and major organic components was analyzed. Then, the causal relationship was verified through enzymatic hydrolysis experiments. The results showed that three or four states of water were found in the 10 varieties of fresh sweet potato residues, namely compound (T21, 0.658–2.310 ms), immobilized (T22, 7.055–21.550 ms), entrapped (T23, 377.410–705.480 ms) and free flowing water (T24, 705.480–3 764.936 ms). The percentage of entrapped water in sweet potato residues was the highest (93.59% on average), followed by immobilized water (5.15% on average). The percentages of compound water and free flowing water were only 0.85% and 0.41%, respectively. The percentage of entrapped water was significantly positively correlated with the contents of pectin, dietary fiber, and insoluble dietary fiber. The amount of water discharged from sweet potato residues significantly increase after being hydrolyzed by pectinase, but did not significantly change after being hydrolyzed by cellulase, hemicellulase or lignin peroxidase. Under scanning electron microscopy (SEM), it was observed that most of starch particles were encapsulated or bound to cell wall debris. This study can provide a theoretical basis for the development of an efficient dehydration technology for sweet potato residues.

In order to explore the pork spoilage potential of Pseudomonas fragi and the antibacterial mechanism of garlic essential oil, P. fragi was isolated from chilled pork under aerobic storage conditions and tested its spoilage capacity. The isolates with strong spoilage capacity were selected for further investigation. The antibacterial activity of garlic essential oil against the selected strains was evaluated by determining the minimum inhibitory concentration (MIC) and plotting the bacterial growth curve. Furthermore, the antibacterial mechanism was investigated by scanning electron microscopic (SEM) observation as well as measuring cell membrane permeability, bacterial motility and metabolic activity. The results showed that P. fragi could cause pork spoilage. Garlic essential oil exhibited a strong inhibitory effect against P. fragi derived from pork, with a MIC of 0.125 μL/mL. Garlic essential oil could disrupt the normal structural morphology of P. fragi, enhance the permeability of the cell membrane, and inhibit bacterial metabolic activity and mobility. The results from this study can provide a theoretical foundation for the application of garlic essential oil as a natural food preservative.

We consider the convolution equation F*X=BF* X=B, where F∈R3×3F\in {{\mathbb{R}}}^{3\times 3} and B∈Rm×nB\in {{\mathbb{R}}}^{m\times n} are given and X∈Rm×nX\in {{\mathbb{R}}}^{m\times n} is to be determined. The convolution equation can be regarded as a linear system with a coefficient matrix of special structure. This fact has led to many studies including efficient numerical algorithms for solving the convolution equation. In this study, we show that the convolution equation can be represented as a generalized Sylvester equation. Furthermore, for some realistic examples arising from image processing, we show that the generalized Sylvester equation can be reduced to a simpler form, and we analyze the unique solvability of the convolution equation.

In order to investigate the effect of long-term consumption of yak milk on the intestinal flora and metabolism and to explore the correlation between acclimation to monodiet and yak milk intake in high-altitude pastoral areas, this study used metagenomics and metabolomics to evaluate the gut microbial community structure and metabolites of mice fed yak milk or Holstein cow milk. Results showed that compared with the control group (normal saline solution), at the phylum level, ingestion of yak milk improved the relative abundance of Actinobacteria (33.27%), Bacteroidetes (24.31%) and Verrucomicrobia (11.08%), while ingestion of Holstein cow milk increased the relative abundance of Firmicutes (43.74%) and Bacteroidetes (24.75%). At the genus level, yak milk consumption increased the relative abundance of Ackermania (11.80%), Bacteroides (6.09%) and Limosilactobacillus (4.77%), while Holstein cow milk consumption increased the relative abundance of Lactobacillus (28.62%), Duncaniella (6.15%) and Limosilactobacillus (6.49%). Both yak and Holstein cow milk up-regulated carbohydrate and nucleotide metabolism. Furthermore, yak milk significantly up-regulated amino acid metabolism, cofactor and vitamin metabolism, energy metabolism, the biosynthesis of secondary metabolites, and the biosynthesis and metabolism of peptidoglycan. Metabolomics revealed that yak milk increased the contents of metabolites such as VB1, (+/-) 12 (13)-DiHOME, coenzyme Q2 and sulfonymethazine, as well as steroid hormone biosynthesis, cofactor biosynthesis, 2-oxyarboxylate metabolism, VB6 metabolism and phenylalanine metabolism in mice. Investigation of intestinal tissue morphology showed that the intestinal wall became thicker with increasing diversity and richness of the gut microbiota and the intestinal villi became longer and denser without deformity or breakage. In conclusion, yak milk has a positive effect on the intestinal flora and metabolism in mice, and this study provides a scientific basis for further development and utilization of yak milk.

An improved acetyl chloride-methanol method was established for the rapid and accurate determination of linoleic acid, α-linolenic acid, docosahexaenoic acid (DHA) and arachidonic acid (ARA) in infant foods for special medicinal purpose with deeply hydrolyzed milk proteins and amino acids. The results showed that the optimal pretreatment conditions were 6 mL of reaction reagent, reaction for 60 minutes, and use of isooctane as extraction solvent. The linear range of linolenic acid and α-linolenic acid were 0.8–8.0 and 0.2–2.0 mg/mL, respectively. The linear ranges of DHA and ARA were 0.02–0.40 mg/mL, and the determination coefficients for all analytes were greater than or equal to 0.999 7. The limits of detection (LOD) and limits of quantitation (LOQ) of the developed method were 2 and 5 mg/100 g, respectively. This method was characterized by good repeatability (relative standard deviation (RSD) ≤ 3.3%), high precision (RSD ≤ 3.8%), good stability (RSD ≤ 2.6%), and high spiked recovery (ranging from 93.1% to 101.7%). Compared with its original version, the developed method could effectively solve the problem of incomplete reaction due to caking, with an at least 100% higher working efficiency.

为解决传统植脂奶油所用部分氢化植物油中饱和脂肪酸与反式脂肪酸带来的健康问题，以椰子油-葵花籽油混合油（质量比1∶ 1）为基料油，β-环糊精和大豆卵磷脂为复合乳化剂，采用物理复配法制备植脂奶油，采用单因素试验研究了水分含量、β-环糊精和大豆卵磷脂添加量对植脂奶油持油性、持水性和稳定性的影响，并通过响应面法优化了制备工艺条件。结果表明：植脂奶油最优制备工艺条件为β-环糊精添加量6.0%、大豆卵磷脂添加量1.1%、水分含量38.0%，在此条件下植脂奶油的持油性和持水性分别达到98.9%和93.8%；对植脂奶油的稳定性分析也进一步说明了持油性、持水性与稳定性之间的正向关系。综上，以β-环糊精和大豆卵磷脂为复合乳化剂，采用物理复配法制备的椰子油-葵花籽油基植脂奶油是一种潜在的营养健康植脂奶油。Aiming to resolve the health issues caused by saturated fatty acids and trans fatty acids in part hydrogenated vegetable oils used in traditional vegetable cream, using coconut oil-sunflower seed oil mixture(mass ratio 1∶ 1 ) as the base oil, β-cyclodextrin and soybean lecithin as compound emulsifiers,vegetable cream was prepared by physical compound method.The effects of water content, addition amounts of β-cyclodextrin and soybean lecithin on the oil holding capacity, water holding capacity, and stability of the vegetable cream were investigated by single factor experiment, then response surface methodology was used to optimize the preparation conditions of vegetable cream. The results showed that the optimal conditions were as follows: β-cyclodextrin addition amount 6.0%, soybean lecithin addition amount 11% and water content 38.0%. Under the optimal conditions, the oil holding capacity and water holding capacity of the vegetable cream reached 98.9% and 93.8%, respectively. Additionally, the analysis of stability of the vegetable cream showed that there was a positive relationship between oil holding capacity, water holding capacity and stability. Coconut oil-sunflower seed oil based vegetable cream prepared by physical compound method with β-cyclodextrin and soybean lecithin as compound emulsifiers is a potential nutritious and healthy vegetable cream.