Galactooligosaccharides in infant formulas: Maillard reaction characteristics and influence on formation of advanced glycation end products.

As prebiotics supplemented in infant formulas (IFs), galactooligosaccharides (GOSs) also have many other biological activities; however, their Maillard reaction characteristics are still unclear. We investigated the Maillard reactivity of GOSs and their effects on advanced glycation end product (AGE) formation during IF processing. The results showed that AGE and HMF formation was temperature-dependent and reached the maximum at pH 9.0 in the Maillard reaction system of GOSs and Nα-acetyl-L-lysine. Acidic conditions accelerated HMF formation; however, protein cross-linking was more likely to occur under alkaline conditions. The degree of polymerization (DP) of GOSs had no significant effect on AGEs formation (except pyrraline); however, the greater the DP, the higher the concentration of HMF and pyrraline. Besides, compared with arginine and casein, lysine and whey protein were more prone to Maillard reaction with GOSs. GOSs promoted AGEs formation in a dose-dependent manner during the processing of IFs. These results provide a reliable theoretical basis for application of GOSs in IFs.

Pectin oligosaccharides from hawthorn (Crataegus pinnatifida Bunge. Var. major) inhibit the formation of advanced glycation end products in infant formula milk powder.

Pectin oligosaccharides (POSs) can not only be used as prebiotics to promote the growth of beneficial bacteria in the intestine but also can be used as natural food-borne antiglycation agents to inhibit the formation of advanced glycation end products (AGEs) in vitro, which is related to their structure, including molecular weight and galacturonic acid content. In this study, haw polysaccharides (HPSs) were isolated and purified, and POSs with high antiglycation activity in vitro were prepared. On this basis, the inhibitory effect of POSs on the formation of AGEs in infant formula milk powder was investigated. The results showed that no obvious inhibitory effect of POSs was found on the formation of AGEs in infant formula milk powder under accelerated storage at 25 °C and 45 °C. But, POSs showed a strong inhibitory effect on the formation of furosine, Nε-carboxymethyllysine (CML), Nε-carboxyethyllysine (CEL) and the total AGEs in infant formula milk powder under accelerated storage at 65 °C. In addition, POSs also had a strong inhibitory effect on the formation of lipid oxidation products but did not affect the formation of protein degradation products. Simultaneously, the cytotoxicity experiments using human umbilical vein endothelial cells showed that the infant formula milk powder supplemented with POSs had the lowest cytotoxicity compared to the blank control (BC) and GOS/FOS supplementation milk powder under accelerated storage at 65 °C, which may be related to the inhibitory effect of POSs on the formation of AGEs in infant formula milk powder. Furthermore, the in vitro fermentation experiments showed that the antiglycation process did not affect the prebiotic activity of POSs in infant formula milk powder.

Copper or Manganese Supplementation Endows the Peptic Hydrolysate from Bovine Lactoferrin with Enhanced Activity to Human Gastric Cancer AGS Cells.

A lactoferrin hydrolysate (LFH) was generated from bovine lactoferrin by pepsin, mixed with Cu2+ and Mn2+ at 0.64-1.28 and 0.28-0.56 mg/g protein, respectively; and then their in vitro effects on human gastric cancer AGS cells were assessed. With incubation times of 24 or 48 h, LFH and its Cu2+/Mn2+ mixtures at 10-30 mg/mL in dose-dependent manner inhibited cell growth; and more, these mixtures showed higher activities than LFH alone. Cell treatments of LFH and the mixtures (25 mg/mL) for 24 h could arrest cell cycle at G0/G1-phase, damage mitochondrial membrane integrity, and induce apoptosis, while the mixtures were also more powerful than LFH to exert these three effects. Higher Cu2+/Mn2+ supplementation level resulted in higher growth inhibition, cell cycle arrest, mitochondrial membrane potential disruption, and apoptosis induction; furthermore, Mn2+ was notable for its higher efficacy than Cu2+ to increase these four effects. Western-blot assay results revealed that four apoptosis-related proteins Bad, Bax, cytochrome c, and p53 were up-regulated, and both caspase-3 and caspase-9 also were cleaved and activated; moreover, two autophagy-related proteins LC3-II and cleaved Beclin-1 were down- and up-regulated, respectively. It is thus concluded that Cu2+ and especially Mn2+ could endow supplemented LFH with increased anti-cancer effects in AGS cells, with two proposed events as enhanced apoptosis induction (via activating apoptosis-related proteins) and autophagy inhibition (via activating autophagy-related proteins).