Chemical Characterization and Nutritional Analysis of Protein Isolates from Caragana korshinskii Kom

Effects of Cellulase and Lactic Acid Bacteria on Ensiling Performance and Bacterial Community of Caragana korshinskii Silage

The aim of this study was to evaluate the effects of cellulase (CE) and lactic acid bacteria (LAB) on Caragana korshinskii silage by analyzing the fermentation parameters, chemical composition, and bacterial community. The Caragana korshinskii was harvested at the fruiting period and treated with cellulase and LAB alone as a control treatment with no additive (CK). The ensiling performance and bacterial community were determined after 3, 7, 15, 30, and 60 days of fermentation process. Compared with the CK group, the pH, dry matter loss, and ammonia nitrogen content were significantly (p < 0.05) decreased in the LAB and CE treatments. Compared with the CK and LAB group, the contents of acid detergent fiber, neutral detergent fiber, and acid detergent lignin in the CE group decreased significantly (p < 0.05), and the water-soluble carbohydrates, acetic acid, and lactic acid concentrations increased significantly (p < 0.05). At the genus level of microorganisms, the addition of cellulase and LAB significantly reduced the microbial diversity. Compared with the CK group (78.05%), the relative abundance of Lactiplantibacillus in the CE group (90.19%) and LAB group (88.40%) significantly (p < 0.05) increased. The relative abundance of Pediococcus in the CE group (3.66%) and LAB group (2.14%) was significantly (p < 0.05) lower than that in the CK group (14.73%). Predicted functional profiling of 16S rRNA genes revealed that the addition of cellulase and LAB increased the pyruvate metabolic pathway during Caragana korshinskii silage, thereby increasing the accumulation of lactic acid concentration. The addition of cellulase expressed a better advantage in the biosynthetic capacity of lysine. In summary, the addition of cellulase and LAB could adjust the bacterial community to improve the silage quality of Caragana korshinskii, and the addition of cellulase exhibited better results than the LAB additives.

Effect of Caragana korshinskii Kom. as a partial substitution for sheep forage on intake, digestibility, growth, carcass features, and the rumen bacterial community

The aim of this study was to verify that Caragana korshinskii Kom. (CK) as a component of sheep forage influences lamb digestibility and rumen fermentation by altering the rumen microbial community. Hence, 12 female Tan sheep were allocated into 2 groups: receiving (CK group) or not (control group) 10% of the diet forage fraction with CK. During the 60-day experiment, growth performance, apparent digestibility, rumen volatile fatty acids (VFAs), and nitrogen balance were measured. Meanwhile, the rumen bacterial community diversity and composition were detected by the 16S rRNA sequence. The results indicated that the apparent digestibility of acid detergent fibre (ADF) tended to be higher (0.05 < P < 0.10), and the feed conversion efficiency was improved (P < 0.05) when CK was offered. Compared to those under alfalfa, the composition and abundance of the rumen microbial community were altered in the CK group, and the phylum Firmicutes, which is involved in promoting fibre digestion, increased in abundance. Moreover, VFAs tended to decrease (0.05 < P < 0.10), and the molar proportion of butyrate declined; similarly, levels of hypoxanthine and xanthine were lower (P < 0.05) in the sheep fed CK and may have been responsible for the decreased abundance of Fibrobacter spp., which are cellulolytic ruminal bacteria associated with VFA production.

Chinese quince seed proteins: sequential extraction processing and fraction characterization

Chinese quince seed proteins were sequentially extracted based on the modified Osborne method. Investigations showed that albumin and glutelin were the major fractions. The physicochemical and functional properties of these two fractions were determined. The results showed that both albumin and glutelin posed appropriate essential amino acid composition and met the minimum recommendation (World Health Organization/Food and Agriculture Organization) for adult diet, except for methionine. The hydrophobicity of albumin and glutelin were 1063.56 and 1170.21, respectively. According to differential scanning calorimeter analysis, the denaturation temperature of albumin and glutelin was 101.44 °C and 108.36 °C respectively, and the glutelin fraction had a better thermal stability. The solubility and apparent viscosity of albumin and glutelin were presented to be greatly influenced by pH values. The water holding capacity and oil adsorption capacity of glutelin were 5.44 g/g and 8.15 g/g, higher than those of albumin which were 3.76 g/g and 3.71 g/g, respectively. Circular dichroism determination revealed albumin and glutelin were mainly composed by α-helix and random coil structures. Albumin and glutelin presented the potential as favorable nutrition and functional additive in food industries.

Physicochemical and functional properties of a protein isolate from maca (Lepidium meyenii) and the secondary structure and immunomodulatory activity of its major protein component

Maca protein isolate (MPI) was extracted from maca root, and its physicochemical and functional properties, and the secondary structure and immunomodulatory activity of its major protein component, MMP, were investigated. The MPI lacked essential amino acids compared with soybean protein isolate (SPI) and casein, but was rich in cysteine and proline. The MPI had rich free sulfhydryl (20.6 μmol g-1), and its surface hydrophobicity (H0, 812.4), oil absorption capacity (7.4 g g-1), foaming capacity (100%) and emulsifying activity (58.2 m2 g-1) were higher than that of SPI. However, the thermal stability (Td, 87.4 °C), foaming stability (75%) and emulsifying stability (26.3 min) of the MPI were weaker than that of the SPI. MMP was a pentamer with a molecular weight of 22 kDa and rich in β-sheets. MMP could significantly enhance the phagocytic capacity and promote the NO, TNF-α and IL-6 secretion of RAW 264.7 cells, involving toll-like receptor 4 and complement receptor 3 mainly.

Isolation of antioxidative peptide from the protein hydrolysate of Caragana ambigua seeds and its mechanism for retarding lipid auto-oxidation

BACKGROUND

Peptides can act as antioxidants in emulsion, although the mechanism involved is poorly understood. Caragana ambigua seed is a potential protein source for which the commercial applications have not been explored yet. In the present study, we aimed to evaluate the bio-economic potential of C. ambigua by isolating and characterizing antioxidative peptides from the protein hydrolysate of its seeds for the purpose of protecting lipids from oxidation.

RESULTS

A novel decapeptide, identified as QITEGEDGGG, was purified by high-protein liquid chromotography based on the enrichment of antioxidant fractions, and its antioxidative activity for walnut oil was evaluated in terms of its effect on oil quality, primary and secondary peroxide formation, oxidation kinetics, and structure of oil droplets. A molecular simulation involving the peptide and fatty acid was carried out aiming to understand the mechanism underlying the prevention of lipid oxidation by the peptide. The peptide effectively scavenged superoxide anions (86.46%), inhibited the rate of linoleic acid oxidation (60.37%) and delayed auto-oxidation of walnut oil. Its inhibition of lipid oxidation was attributed to the protection of phenolic compounds and polyunsaturated fatty acids of walnut oil.

CONCLUSION

The findings of the present study will help in the exploitation of novel antioxidant peptides of lipids from woody seed-based protein sources such the seeds of C. ambigua trees. © 2018 Society of Chemical Industry.

Physicochemical and functional properties of Chinese quince seed protein isolate

Chinese quince seed protein isolate (CPI) was extracted using aqueous extraction and the isoelectric precipitation method, and its physicochemical and functional properties were investigated. Results showed that CPI contained all essential amino acids with exception of methionine which met the minimum recommendations for adults (World Health Organization/Food and Agriculture Organization). The electrophoresis analysis of sodium dodecyl sulphate polyacrylamide gel indicated that the molecular weights of protein fractions were approximately 15-60 kDa. Differential scanning calorimetry analysis was conducted, and the denaturation temperature of CPI was 103.4 °C. The surface hydrophobicity of CPI was found to be 932.80. The experiments showed that CPI had high emulsifying capacity, foaming stability, water holding capacity and oil adsorption capacity. Moreover, CPI also had outstanding gel formation capacity since its least gelation concentration of CPI was only 8%. All these results implied that CPI could be a nutritional protein resource and functional ingredient in the food industry.

Chemical Utilization of Albizia lebbeck Leaves for Developing Protein Concentrates as a Dietary Supplement

In search of nonconventional sources of protein to combat widespread malnutrition, the possibility of developing a protein concentrate as an alternative dietary supplement from abundantly available yet poorly valorized leaves of Albizia lebbeck (siris) was examined. A process for recovery of leaf protein concentrate (LPC) from these leaves was optimized and applied for isolation of LPCs from lower, middle, and upper canopies of the tree. The optimized conditions (leaves to water 1:9, coagulation at pH 4.0 using 1 N citric acid at 90°C for 11 minutes) afforded LPCs containing protein 37.15%, 37.57%, and 37.76% in 5.99%, 5.97%, and 6.07% yield, respectively. The proximate nutritional composition, pigments, minerals, in vitro digestibility, and antinutritional factors of these LPCs were determined. Analysis of variance of these data revealed no significant difference with respect to canopy. Use of Albizia lebbeck leaves for development of LPC as a food/feed supplement was revealed.