Biochemical and protein nutritional potential of mulberry (Morus alba L.) leaf: partial substitution improves the nutrition of conventional protein.

BACKGROUND: With the requirements of environmental, cost and economic sustainability, new sources of alternative proteins in the livestock industry are receiving increasing attention. Mulberry (Morus alba L.) leaves are a unique feed resource because of their high protein content and large availability. Therefore, mining sustainable protein suitable for the animal husbandry industry in sericulture resources could achieve a win-win situation. RESULTS: The protein content in mulberry leaves is 232.10-386.16 g kg-1 , and the mean value of crude fat content is 43.76 ± 8.48 g kg-1 , which has the advantages of protein content and energy. In addition, the average content of phytic acid in mulberry leaves is only 1.88 ± 0.56 g kg-1 , which means that it is not inhibited in terms of nutrient absorption. Meanwhile, the digestibility of protein was Bean pulp > Sample 8 ≈ Alfalfa ≈ Sample 13 ≈ Cottonseed meal > Fish meal, and the ß-turn and particle size of mulberry leaf protein are more conducive to digestion in vitro. Furthermore, the protein of Sample 13 had the richest essential amino acids (252.00 g kg-1 ) and the highest essential amino acid index (EAAI), which was superior to conventional feed protein. In addition, the partial substitution of mulberry leaf protein (15%) significantly increased the EAAI value of conventional feed protein. However, to balance nutrition, it is necessary to combine mulberry leaf protein with other proteins to further broaden its application field. CONCLUSION: Mulberry leaves are a new source of feed protein, which helps to alleviate the two major problems of mulberry resource surplus and feed protein resource shortage. © 2023 Society of Chemical Industry.

Mulberry (Morus alba L.) leaf powder modified the processing of meat alternatives: Principal component analysis from apparent properties to chemical bonds.

For texture control in plant-meat alternatives, the interrelationship between apparent characteristics and chemical bonds in high-fiber formulations remains unclear. The influence of mulberry leaf powder on apparent characteristics and chemical bonds of raw materials, block and strip products at addition amounts of 0.5-25% was analyzed. The results showed that 8% addition significantly increased the chewiness of the block by 98.12%. The strips' texture shows a downward trend, and the processing produced more redness and color difference. Additives promoted the formation of voids, lamellar and filamentous structures, and the strip produced more striped structures. Disulfide bonds significantly increased in the block, and the ß-turn in the secondary structure enhanced by 12.20%. The ß-turn transformed into a ß-sheet in strips. Principal component analysis revealed that the texture improvement was associated with producing disulfide bonds and ß-turn, providing a basis for high-fiber components to improve products' apparent characteristics by chemical bonds.

A Novel Low Molecule Peptides-calcium Chelate from Silkworm Pupae Protein Hydrolysate: Preparation, Antioxidant Activity, and Bioavailability.

BACKGROUND: The antioxidant properties of active peptides from silkworm pupae protein hydrolysate are of interest, and it serves as a novel source of calcium supplement. METHODS: Optimize the preparation parameters of silkworm pupae bioactive peptide-calcium chelate, and investigate the mechanism and bioavailability of silkworm pupae active peptide as a transport carrier to promote calcium ion absorption using simulated gastrointestinal digestion and Caco-2 monolayer cell model. RESULTS: The optimal process parameters for preparing peptide calcium chelate were the peptide calcium mass ratio of 3:1, pH of 6.7, a temperature of 35.6°C, and time of 32.8 min by Box-Behnken design, and the calciumchelating rate reached 84.67%. The DPPH radical scavenging activity of silkworm pupae protein hydrolysatecalcium chelate was 79.36 ± 4.31%, significantly higher than silkworm pupae protein hydrolysate (61.00 ± 9.56%). Fourier transform infrared spectroscopy shows that the COO-, N-H, C-H, and C-O groups participated in the formation of silkworm pupae protein hydrolysate-calcium chelate. The particle size of the silkworm pupae protein hydrolysate-calcium chelate was 970.75 ± 30.12 nm, which was significantly higher than that of silkworm pupae protein hydrolysate (253.14 ± 5.72 nm). The silkworm pupae protein hydrolysate-calcium chelate showed a calcium dissolution rate of 71.01 ± 1.91% in the simulated intestinal phase, significantly higher than that of CaCl2 (59.34 ± 1.24%). In the Caco-2 cell monolayers, the silkworm pupae protein hydrolysatecalcium chelate was more favorable for calcium transport. CONCLUSION: A novel silkworm pupa protein hydrolysate-calcium chelate with high antioxidant activity was successfully prepared to improve the bioavailability of calcium.

An alternative solution for α-linolenic acid supplements: in vitro digestive properties of silkworm pupae oil in a pH-stat system.

α-Linolenic acid (ALA) is recognised to have a regulatory effect on cardiovascular diseases. Due to the low bioavailability of linseed oil (LINO), which is the most common ALA supplement, it is necessary to find a replacement for ALA supplements that is more easily accepted by the human body. The content of ALA in silkworm pupae oil (SPO) is 32.60 ± 0.67%, and SPO can be substituted as a dietary lipid to meet the demand of the human body. In the present study, a pH-stat system was used to investigate the release degree of free fatty acids (FFAs) from SPO and construct a first-order kinetic model. Digestion experiments in vitro with different lipids showed that the maximum release FFA levels were SPO > SO (soybean oil) > LO (lard oil) > MSO (mulberry seed oil) > LINO, and the first-order kinetic apparent rate constants were LINO > SPO > LO > SO > MSO. Triacylglycerol (TAG) and fatty acid composition are the decisive factors in determining the level of lipid digestion. Therefore, the maximum level of FFAs released from SPO (84.34 ± 1.37%) was much higher than that of LINO (49.78 ± 0.52%) when the hydrolysis rates were 0.2114 s-1 and 0.2249 s-1, respectively. In addition, the smaller emulsion droplet size (609.24 ± 43.46 nm) and weaker surface charge (-17.93 ± 0.42 mV) also resulted in higher levels of SPO under in vitro digestion conditions. Meanwhile, due to low melting and crystallisation temperature, SPO is quickly absorbed by the human body. Overall, SPO can be used as a new alternative for ALA supplements based on its superior digestive properties.