Proliferation of Bifidobacterium L80 under different proportions of milk protein hydrolysate.

The intestinal microecological environment is critical to an infant's growth. For those infants consuming milk power, it is very important to improve the intestinal microecological environment to promote the healthy growth of infants. In this paper, Milk protein hydrolysate (MPH), consisting of different proportions of proteins and small molecule peptides (5:5, 4:6, 3:7, 2:8, 1:9) were added to infant formula powder (IFP). The effects of MFP-enriched IFP addition on proliferation and metabolism of Bifidobacterium L80 were studied. Compared with MPH-free IFP, MFP-enriched IFP with 1:9 of proteins to small molecule peptides significantly enhanced the proliferation of Bifidobacterium L80, resulting in higher cell density, greater viable counts and higher titratable acidity. MFP-enriched IFP increased the content of seven organic acids and H2O2 in the system, and improved the antibacterial activity to E. coli BL21. This study suggested that MPH could be an effective addition to infant formula powder to promote the growth of Bifidobacterium, so to improve the intestinal health of infants.

Structural characterization and functional properties of CNPP, a byproduct formed during CPP preparation.

Casein nonphosphopeptide (CNPP), a byproduct formed during the preparation of casein phosphopeptide (CPP), is often discarded on a large scale. Although our previous studies have demonstrated the ameliorative effect of CNPP on muscle wasting disorders, its structure-function mechanism is still unclear. Therefore, considering the great influence of structural characteristics on function, this study aims to explain the potential mechanism by characterizing the physicochemical and functional properties of CNPP. The results of structural characterization indicated that CNPP was of low molecular weight and composed of the complete range of amino acids; it was particularly rich in leucine. Compared with casein, CNPP had a lower molecular size and total/free sulfhydryl content (reduced 2.44 and 2.02 µmol/g in CNPP, respectively). Additionally, Fourier transform infrared spectroscopic analysis revealed that enzymatic hydrolysis caused protein unfolding, and the content of ß-turns and random coils reached 50.20% and 10.67%, respectively. Fluorescence-dependent detection of CNPP indicated a reduction of spectral intensity and the occurrence of a red shift. The changes in the structure of CNPP significantly affected its functional characteristics. CNPP has better solubility, foaming, and digestion properties than those of casein and whey protein. Specifically, the foam stability and emulsification properties decreased in the order of casein > CNPP > whey protein. The present study can provide a substantial basis for future application of CNPP as a functional ingredient against sarcopenia.

The influence of soy protein hydrolysate (SPH) addition to infant formula powder on Streptococcus thermophilus proliferation and metabolism.

Nowadays, more and more infants are getting allergic to cow's milk protein, so it is urgent to search for infant formula powder with milk protein alternatives. In the present work, soy protein hydrolysate (SPH) was added to protein-free infant formula powder and the effects of SPH addition on proliferation and metabolism of Streptococcus thermophilus were studied. Compared with commercially available infant formula powder (CK) and protein-free milk powder (BK), the infant formula powder with 20% SPH significantly enhanced the proliferation of S. thermophilus in MRS medium, resulting in a higher cell density and greater viable counts. Moreover, the influence of SPH on the metabolism of S. thermophilus was investigated by analyzing the content of seven organic acids and H2O2 in the medium. The higher content of organic acids and H2O2 is consistent with the stronger antibacterial activity to Escherichia coli. As a consequence, the addition of SPH to infant formula powder can effectively promote the growth of probiotics and SPH may be a promising protein alternative in the infant formula powder.

Effects of soy protein isolate hydrolysates on cholecystokinin released by rat intestinal mucosal cells and food intake in rats.

Soy protein isolate hydrolysates (SPIH) were prepared from soy protein isolate (SPI). Effects of SPIH on a satiety signal cholecystokinin (CCK) and feeding behavior in rats were investigated. SPIH induced more CCK release (164.66 ± 2.40 pg/mL) by rat intestinal mucosal cells than SPI (143.33 ± 3.71 pg/mL). Meal size (MS), intermeal interval (IMI), and satiety ratio (SR = MS/IMI) of rats received different daily doses of SPIH or dietary fiber were detected for 40 days. A 100 mg/kg dose of SPIH resulted in a greater SR than an identical dose of dietary fiber, while a 300 mg/kg dose resulted in a less MS and IMI. A 500 mg/kg dose of SPIH had similar effects to the same dose of dietary fiber on reducing MS, extending IMI, and increasing SR, but resulted in a significantly less body weight at the end of the experiment (318.15 ± 17.83 g) than the dietary fiber group (340.28 ± 6.15 g).

Effects of casein non-phosphopeptide on the development of rat muscle analyzed using computed tomography scanning technology.

The effects of casein non-phosphopeptide (CNPP) on the muscle development of healthy rats and selected blood hormones levels were investigated. CT technology and the ELISA kit were employed to detect the cross-sectional area of each muscle group and blood hormone levels, respectively. The cross-sectional area of the trunk and lower limb muscles of resistance exercise group (REG) rats that were administered a high daily dose of CNPP for 50 days increased more significantly than that of the blank group rats, no exercise group (NEG) rats administered with the same daily dose of CNPP, and REG rats administered with the same daily dose of lactalbumin (P < 0.05).The more enhanced development of trunk and lower limb muscles in CNPP-administered REG rats was associated with a higher blood level of insulin, while no clear trends in blood levels of growth hormone and testosterone were observed. The present results have demonstrated that a combination of physical exercise and diet supplementation with CNPP can synergistically improve muscle mass.