Soy protein isolate (SPI) was grafted with gum acacia (GA) in this work. In comparison with classical heating at high water activity, ultrasound could accelerate the graft reaction between SPI and GA. A degree of graft (DG) of 34 was obtained by ultrasonic treatment for 60 min, whereas 48 h was required with classical heating. Ultrasonic treatment improved the concentration of available free amino groups of SPI. The grafted SPI showed significantly (p < 0.05) higher levels of emulsifying activity index, emulsifying stability index, and surface hydrophobicity than native SPI. The droplet size (D[3,2] and D[4,3]) of SPI emulsion decreased from 8.3 to 2.3 microm and from 25.7 to 7.1 microm through ultrasound-assisted grafting, respectively. Moreover, SPI-GA conjugates gave emulsions exhibiting more stability against creaming than those prepared with only SPI during ambient temperature storage (20 days). Decreases of lysine and arginine contents during the graft reaction indicated that these two amino acid residues attended the covalent linkage between SPI and GA. The results of secondary structure suggested that grafted SPI had decreased alpha-helix and beta-sheet levels and increased unordered coils level.

Mu L., Zhao H., Zhao M., Cui Ch., Liu L. (2011): Physicochemical properties of soy protein isolatesacacia gum conjugates. Czech J. Food Sci., 29: 129-136.Protein-polysaccharide conjugates were generally prepared by dry-heating. However, it was time-consuming and the sample gained was inhomogeneous. A faster way of preparing protein-polysaccharide conjugates is needed. Accordingly, soy protein isolates (SPI)-Acacia gum (GA) conjugates prepared by the wet-heating method were studied in the present work. Physicochemical properties of SPI-GA conjugates were also determined. The results showed that the wet-heating method could improve the rate of the graft reaction of protein and polysaccharide. The solubility of SPI-GA conjugates was significantly (P < 0.05) higher than that of unreacted SPI-GA mixtures and SPI at the same pH values. The emulsion activity index (EAI) of the grafted SPI increased remarkably. Moreover, a significant (P < 0.05) improvement on the emulsifying stability index (ESI) was observed and emulsions with a smaller droplet size were obtained. No visible flocculation during extended storage (30 days) was observed. The time course of the development of the graft reaction of SPI with GA was also shown by SDS-PAGE.

Cantonese sausage is one of the traditional meat products in China. In the present study, eight Cantonese sausage samples from different manufacturers were collected. Their microbial and textural properties were characterized. The chemical compositions were determined as follows: moisture, 15.18 ± 3.40%; protein, 33.75 ± 7.26% (expressed in dry matter); fat, 42.12 ± 6.64% (expressed in dry matter); total carbohydrates, 9.11 ± 3.73%; sodium chloride, 6.13 ± 0.41%; and sodium nitrite, 35.55 ± 6.69 mg/kg. The pH was determined to be 6.22 ± 0.14, while the acid value was 2.02 ± 0.71 mg potassium hydroxide/g lipid, and the peroxide value was 0.03 ± 0.04 g potassium iodide/100 g lipid. The total viable counts were 5.55 ± 1.48 log10 cfu/g, lactic acid bacteria were 3.59 ± 0.68 log10 cfu/g, staphylococci/micrococci were 3.96 ± 0.54 log10 cfu/g and yeasts/molds were 3.55 ± 0.47 log10 cfu/g. Staphylococci/micrococci were the dominant microbial group in Cantonese sausage. This was different from other sausages. The textural profiles of Cantonese sausage were determined as follows: average values of hardness, springiness, cohesiveness, gumminess and chewiness were 3,066.56 g, 0.96 mm, 0.57, 1,736.76 g and 1,658.26 g × mm, respectively. Analysis of between‐variable relationships indicated that the pH value of Cantonese sausage was significantly correlated to its microbial and textural properties. PRACTICAL APPLICATIONS Cantonese sausage has gained much popularity and acceptance in China and many other countries. Commercial products from different manufacturers were collected in this work. The microbiological and textural characteristics of Cantonese sausage as well as the chemical compositions were evaluated. It is helpful to understand this type of sausage in order to improve its quality.

Silkworm pupa oil (SPO) is considered excellent dietary supplements for hyperlipidemia in China. However, more knowledge is needed about the SPO given its potential use as a functional food with hypolipidemic effect. Quantification and qualification of fatty acids in SPO were carried out by GC‐MS.Five saturated fatty acids (SFAs) and four unsaturated fatty acids (UFAs) were found in SPO, and up to 70% of SPO are unsaturated. Oleic Acidis present in the highest concentration (34.45%) followed by 29.18% α‐ linolenic acid. Fatty Acids (%) Silkworm Pupa Oil (%) Lauric Acid (C12: 0) 0.093 Myristic Acid (C14: 0) 0.19 Palmitic Acid (C16: 0) 23.91 Stearic Acid (C18: 0) 4.6 Eicosanoic Acid (C20: 0) 0.17 Palmitoteic Acid (C16:1) 1.28 Oleic Acid (C18: 1, n‐9) 34.45 Linoleic Acid (C18: 2, n‐6) 6.13 Linolenic Acid (C18: 3, n‐3) 29.18 Saturated fatty acids (SFAs) 28.96 monounsaturated fatty acids (MUFAs) 35.73 Polyunsaturated fatty acids (PUFAs) 35.31 n‐3/n‐6 4.76 UFAs/SFAs 2.45 Effect of SPO on dyslipidemic Wistar rats adapted to high‐fat diets was investigated. 6‐week SPO supplementation resulted in lower concentrations of serum TC and LDL‐C (P蠄 0.05) statistically as compared to HFDC group. Group Dose (mL/kg/d) TC mmol/L TG mmol/L LDL‐C mmol/L HDL‐C mmol/L LDL‐C/ HDL‐C NC vehicle 2.48 ± 0.33a 0.60 ± 0.10 1.13 ± 0.12a 1.47 ± 0.15 0.87 ± 0.056a HFDC vehicle 3.77 ± 0.41c 0.69 ± 0.23 2.53 ± 0.31d 1.38 ± 0.28 2.51 ± 0.47b SPO 1 2.95 ± 0.35b 0.68 ± 0.24 1.75 ± 0.48cd 1.34 ± 0.45 2.79 ± 1.27b SPO 2 2.13 ± 0.44a 0.65 ± 0.16 0.75 ± 0.24b 1.51 ± 0.34 2.09 ± 0.85b SPO 4 2.34 ± 0.58a 0.70 ± 0.19 0.97 ± 0.28bc 1.51 ± 0.35 2.17 ± 0.89b High and middle dose of SPO supplementation (2, 4 mL/kg/d) resulted in higher T‐AOC, SOD and GSH‐Px level and lower MDA level(P蠄0.05) both in serum and liver against HFDC group. Taken together, SPO can help improve lipid profile and alleviate oxidative stress in dyslipidemic rats induced by high‐fat‐diets. It is suggested that SPO may be beneficial as treatment for hyperlipidemia.