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关键词： Acid-induced gel   Lactic acid bacteria   Organic acid   Glucono-6-lactone   Physicochemical properties  

摘要： This study evaluated the differences in the physicochemical, digestion and microstructure of soy protein gels acidified with Lactobacillus casei (L. casei), glucono-6-lactone (GDL) and citric acid. The maximum acidification rate was as follows: citric acid > GDL > L. casei. The gelation points of L. casei-induced gel (LC gel) and GDLinduced gel (GDL gel) occurred at 74 min and 55 min;however, gelation point of citric acid-induced gel (CA gel) was not detected because acidification was too fast. LC gel showed the high gel hardness (20.40 +/- 2.23 g) and water holding capacity (84.58 +/- 0.59%). At the end of intestinal digestion, the average particle size of the LC gel was the largest, but there was no significant difference between GDL gel and CA gel. The microstructure of the GDL gel was found to be the densest. Acidification rate was the "key step" of acid-induced gels, while both the proteolytic and exopolysaccharide (EPS) production capacity were involved in LC gel.

关键词： Microspheres   Lysozyme   Chitosan   Immobilization   Cross-linking   Antimicrobial activity  

摘要： Chitosan microspheres (CMS) by the emulsion-chemical cross-linking method with and without lysozyme immobilization were synthesized and characterized. The technique conditions were adjusted, and spherical particles with approximate diameters of 3.74 +/- 1.08 mu m and 0. 29 +/- 0.029 mu m to CMS and chitosan-lysozyme microspheres (C-LMS), respectively, were obtained. The microspheres were characterized by scanning electron microscopy (FESEM), Spectroscopy Fourier Transform Spectroscopy (ATR-FTIR), X-ray diffraction (XRD), and zeta potential. Particle size was identified by laser light scattering (DLS) and the thermal properties by Differential Scanning Calorimetry (DSC) and Thermogravimetry (TGA) were determined. By the lysis of Micrococcus lysodeikticus, the activity of the microspheres was determined, and the results correlated with the amount of lysozyme used in the immobilization process and the enzyme loading efficiency was 67%. Finally, release tests pointed out the amount of enzyme immobilized on the microsphere surface. These results showed that chitosan microspheres could be used as material for lysozyme immobilization by cross-linking technique. The antimicrobial activity was tested by inhibition percent determination, and it evidenced both chitosan microspheres (CMS) and chitosan-lysozyme microspheres (C-LMS) positive antimicrobial activity to Staphylococcus aureus, Enterococcus faecalis and Pseudomonas aeruginosa.

关键词： Starch   SGAP   Annealing   Dual-treatment  

摘要： The effect of removal of starch granule associated proteins (SGAPs), annealing and dual-treatment on physicochemical properties of three rice starches with different amylose content (AC) was investigated. SGAPs removal reduced stability of starch granules, thus increasing amylose leaching, swelling power, solubility, and pseudoplasticity of Qiuguang (15.6% AC) and Luhui (22.1% AC) rice starches, decreasing pseudoplasticity of Yangfunuo (1.56% AC) starch, and decreasing To, Tp, and Tc, pasting viscosity and storage modulus of all three rice starches. Annealing decreased amylose leaching of the three starches, and pasting properties, pseudoplastic and storage modulus of Yangfunuo starch, but increased swelling power of the three starches, Delta H and To of Qiuguang starch, and pasting properties and pseudoplasticity of Qiuguang and Luhui starches. The effect of dual-treatment was generally the sum of effect of SGAPs removal and annealing treatment. But an interaction effect of the dualtreatment was observed for some parameters. The effect of annealing was closely related to the variety and composition of the starch.

关键词： Polyalkoxylated fatty alcohol   green surfactant   surfactant mixture   mutual interaction  

摘要： The concentration-dependent physicochemical behaviors of the binary mixtures of polyalkoxylated fatty alcohol (PAFA)-AS (alkyl sulfonate), PAFA-CB (cocamidopropyl betaine) and PAFA-APG (alkyl polyglucosides) and their micellar interactions were determined at the ratios of 9:1, 8:2, 7:3 and 6:4 (w/w). At concentrated level, the rheological study of all the PAFA-mixed surfactants display a Newtonian behavior at low viscosities. Prominent discrepancies among the mixed surfactant systems were observed after stepwise dilution of the samples. In tensiometry study, the types of mutual interaction in the mixed surfactant systems were evaluated by regular solution theory (RST). The CMC(exp)curves of PAFA-AS and PAFA-CB systems demonstrate lower position than their CMC(theo)curves signifying that these nonionic-anionic and nonionic-zwitterionic samples behave nonideal showing synergistic interaction between individual components in the mixed micelles, as further verified by the negative values of interaction parameter beta and activity coefficientsf(1)andf(2)are less than 1. Meanwhile, the PAFA-APG system shows no significant mutual interaction between the nonionic-nonionic components in the mixed micelles. TEM micrographs depict the formations of branched wormlike micelles and multiconnected threadlike networks for the PAFA-AS and PAFA-CB systems, respectively, while gigantic multilamellar vesicles for the PAFA-APG system. Upon dilution of these mixed surfactants to CMC, the mixed micelles are in monodisperse sizes of less than 15 nm and in various magnitudes of zeta potential ranging from -2.92 to -21.87 mV.

关键词： Starch   Gelatin   Lipids   Edible film   Extrusion blowing  

摘要： The effects of various physical state lipids (rapeseed oil (RO), shortening (ST), beeswax (BW)), on the physicochemical properties of starch (S) (hydroxypropyl distarch phosphate (HP), oxidized hydroxypropyl starch (OS))/gelatin (G) blown films were studied. S/G-lipid blends showed decreased storage modulus and complex viscosity. The formation of hydrogen bonds was inhibited by the ST and BW, but facilitated by the RO. Compared with BW and ST, RO was more effective to promote the melted and fractured of starch. Lipids addition promoted the compatibility of starch and gelatin. The presence of the lipids significantly improved the surface hydrophobicity, mechanical, water vapor barrier and water resistance properties of S/G films. S/G-RO films exhibited the strongest surface hydrophobicity and tensile strength, while HP/G-BW film showed the strongest water resistance and water vapor barrier properties. These results revealed that the appropriate lipids could be used to produce S/G-lipid films with desirable physicochemical properties.

关键词： LF‐   NMR   MRI   mackerel   frying   distribution of water and lipid  

摘要： BACKGROUND In this work, low-field nuclear magnetic resonance (LF-NMR) and magnetic resonance imaging were used to investigate the changes in protons (from water and oil) distribution of mackerel during the frying process. The relationship between proton migration and some physicochemical indexes was established by partial least squares regression (PLSR). The changing mechanism of the quality characteristics and physicochemical properties of fish meat under different frying conditions was analysed by LF-NMR combined with PLSR, which provided theoretical support for the development of canned mackerel food. RESULTS LF-NMR results showed that three kinds of T-2 protons assigned to protein-water interaction (T-21), multilayer bound water (T-22), oil and free water (T-23), respectively. As the frying temperature increased, protons from the T-22 peak significantly decreased, while protons from the T-23 peak remarkably increased. The microstructure of fried mackerel was destroyed;cooking loss, oil content, a* value, b* value, hardness and chewiness increased;and the protein content and L* value decreased. Furthermore, PLSR analysis revealed that significant correlation was observed between the cooking loss, TPA parameter (chewiness), colour parameter (L*) and LF-NMR parameters. CONCLUSION Different frying temperatures and times had a strong effect on the physicochemical properties of mackerel. Good prediction models could be established by proton migration using the LF-NMR technique and PLSR for fried mackerel. Quality control of fried fish could be realized by monitoring the change in LF-NMR data. (c) 2021 Society of Chemical Industry

关键词： acacia seed species   regions   nutritional quality   anti‐   nutrients   antioxidant capacity   functional properties  

摘要： BACKGROUND Acacia seed (AS) is an underutilized legume widely distributed in the world, with majority of the species (>70%) found in Australia. Generally, the seeds are not only rich in protein, dietary fibre and potassium, but also possess anti-nutritional compounds. In recent years, there have been an increase in the cultivation of some Australian acacia species such as Acacia victoriae, Acacia cowleana and Acacia coriacea from different regions. However, there is limited information on the composition, anti-nutrients, antioxidant and functional properties of flour from these widely grown Australian AS species. Thus, the present study aimed to assess the properties of these Australian AS species from different geographical regions. RESULTS The A. cowleana and A. coriacea were characterized by high protein, fat, potassium and soluble carbohydrate. However, higher starch and fibre contents were present in A. victoriae. Greater amounts of anti-nutrients, total phenolics and flavonoids were found in A. cowleana and A. coriacea seeds, whereas A. victoriae had higher 2,2-diphenyl-1-picrylhydrazyl radical-scavenging capacity. A. victoriae and A. coriacea demonstrated the highest water absorption and solubility index, respectively. However, A. cowleana showed the highest oil absorption index. There was less variation in the composition and properties within species from different regions. CONCLUSION All samples showed promising nutritional characteristics, although with sufficient diversity to indicate that Australian acacia seeds can be utilized to develop a range of new (functional) food products. Overall, the information obtained will help the food industries with the selection of AS species for food application.

关键词： channel catfish by‐   products   dynamic rheology   transglutaminase cross‐   linking   protein gel   scanning electron microscopy  

摘要： BACKGROUND Channel catfish farming is very important aquaculture industry in the southern states of the USA. However, huge amounts of by-products are generated from catfish fillet-processing. The by-products (mostly heads and bone frames) are excellent sources of proteins. Currently, catfish by-product has little value, and is regarded as a 'waste', which if not utilized properly could cause serious environmental pollution. Therefore, to find a way to utilize those by-products is critical for the economy of aquaculture. METHOD Protein isolates were extracted from the mixture of catfish by-products (heads and frames) under different alkaline conditions (pH 7.5-11) and made into protein gels. Secondary structures of extracted protein isolates were studied. Microbial transglutaminase (MTGase, 0-4 U g(-1) proteins) was incorporated to improve gel structure. Gelling, physicochemical, textural and thermal properties of protein gels treated with/without MTGase were investigated. Protein pattern changes of MTGase-treated protein gels were studied and the microstructure of the protein gels was analyzed. RESULTS Alpha-helicity of protein isolates made at pH 11 was 21.5% lower than that extracted at pH 8.5. Storage modulus (G ') of protein gel decreased with increasing extraction pH (pH > 9) of the corresponding protein isolate. MTGase treatment exhibited significant effects on denaturation temperature and enthalpy of protein gels. Excessive MTGase (>2 U g(-1)) could weaken the gel structure. CONCLUSION Protein isolates can be extracted from catfish by-products and made into protein gels, which are a value-added product. (c) 2021 Society of Chemical Industry

关键词： wheat bran   solid‐   state fermentation   S   cerevisiae   L   Plantarum   whole wheat bread  

摘要： BACKGROUND The addition of wheat bran (WB) could improve the nutritional quality of whole wheat bread (WWB);however, it also caused many negative effects on the quality of bread. To improve the physico-chemical properties of WB and the quality of WWB, WB was solid-state fermented with different ratios of commercially available S. cerevisiae and L. plantarum, and utilized to prepare WWB. RESULTS The physico-chemical properties of WB including dietary fiber content and its components, amino acid composition, and antioxidant activities were determined. After solid-state fermentation, the physico-chemical properties of WB were improved. WBSac:Lac = 2:1 showed higher antioxidant activity (only the total antioxidant activity was slightly lower than WBSac:Lac = 1:1), and greater concentration of soluble dietary fiber (9.22%) and essential amino acids / total amino acids (42.04) than the other WB samples. Whole wheat bread quality was investigated by measuring specific volume, porosity, texture, aroma, and volatile compounds. The WWB made with WBSac:Lac = 2:1 showed a higher specific volume, more uniform porosity structure, better texture, and more volatile compounds than the other samples. CONCLUSION Using a ratio of yeast and lactobacilli of 2:1, the solid-state fermentation maximally improves the processing properties of WB, and prepares WWB with the best quality. (c) 2021 Society of Chemical Industry

关键词： Montanera   Iberian pig   Dry-cured sausages   Lipid oxidation   Protein oxidation   Tocopherol   Unsaturated fatty acid   Long-term storage  

摘要： Physico-chemical and sensory analysis of Iberian chorizo manufactured from three commercial categories raw material compiled in the current Spanish Iberian Quality standard (Black, Red;100% Iberian and 50% Iberian x Duroc pigs, respectively, under Montanera, and White;50% Iberian x Duroc pigs commercially fed) and packed under vacuum and modified atmosphere (MAP) were carried out, in order to address the influence of the genotype and animal production system and packaging on quality parameters, as well as the stability of these throughout long-term storage. Montanera categories showed higher values of gamma-tocopherol, mono-and poly-unsaturated fatty acids, greater scores of flavour and taste and higher lipid oxidation during the whole storage. MAP preserved better colour, especially redness and lipid oxidative status. Iberian chorizo could attain a differentiated quality because of physico-chemical and sensorial characteristics derived from the Montanera that would be adequate preserved in both vacuum and MAP throughout long-term storage.