The triacylglycerol structure and composition of a human milk fat substitute affect the absorption of fatty acids and calcium, lipid metabolism and bile acid metabolism in newly-weaned Sprague-Dawley rats.

In this study, the effect of sn-2 palmitic triacylglycerols (sn-2 palmitic TAGs) and the ratio between the two major sn-2 palmitic TAGs (OPL to OPO ratio) in a human milk fat substitute (HMFS) on growth, fatty acid and calcium absorptions, and lipid and bile acid metabolic alterations was investigated in Sprague-Dawley rats. After 4 weeks of high-fat feeding, rats fed with the HMFS containing a sn-2 palmitic acid content of 57.87% and an OPL to OPO ratio of 1.4 showed the lowest TAG accumulation in their livers and hypertrophy of perirenal adipocytes, compared to the groups fed with fats containing a lower sn-2 palmitic acid content or a lower OPL to OPO ratio. Meanwhile, synergistically improved absorption of fatty acids and calcium and increased levels of total bile acids (BAs), especially for the tauro-conjugated BAs (TCDCA, TUDCA, TαMCA, TßMCA, TDCA and TωMCA), were observed in rats by both increasing the sn-2 palmitic acid content and the OPL to OPO ratio in HMFS. In addition, the levels of total BAs and tauro-conjugated BAs were negatively correlated with serum TAG, TC, and LDL-c levels and positively correlated with HDL-c levels according to Spearman's correlation analysis (P < 0.05). Collectively, these findings present new nutritional evidence for the potential effects of the TAG structure and composition of a human milk fat substitute on the growth and lipid and bile acid metabolism of the host in infancy.

The structural and functional characteristics of soluble dietary fibers modified from tomato pomace with increased content of lycopene.

The tomato pomace, a by-product of tomato processing, was rich in nutrients such as lycopene (Lyc), vitamins, phenols and soluble dietary fibers (SDF). Homogenization combined with enzymatic hydrolysis (HE) was firstly applied to obtain HE-pomace. The yield of Lyc was raised by 57.2% after HE treatment by the optimal condition. The extraction rate of HE-SDF was increased by 73.4%. In order to clarify the relationship between the SDF and the release of Lyc, SDFs were characterized by structural analysis and morphological determination. The results suggested that HE-SDF possessed smaller molecular weight and loose microstructure with shorter chains. It implied that the degradation of dietary fiber led to the release of Lyc molecules. Besides, HE-SDF exhibited stronger capacity of water-holding, glucose adsorption and bile acid binding. In conclusion, HE treatment possessed the potential to be applied as an excellent modification method, which improved the nutritional and economic value of tomato pomace.

Gelling and bile acid binding properties of gelatin-alginate gels with interpenetrating polymer networks by double cross-linking.

Interpenetrating polymer network (IPN) is an effective method to improve functional properties of hydrogels by forming cross-linking networks. In this study, the gelatin-alginate gels formed by the combination of enzymatic and ionic cross-linking were called IPN gels. Meanwhile, the gels with the treatment of only transglutaminase (TG) or Ca2+ were named as G-semi-IPN and A-semi-IPN, respectively. The formation of semi-IPN and IPN was confirmed by studies on rheology, thermodynamics and micro-morphology. The results showed that the IPN gels had improved gelling properties and structural stability. The functional properties of different gelatin-alginate gels were also investigated. It was firstly found that the IPN gels could enhance mechanical properties, decrease swelling capacity and had better bile acid binding capacity. These results of gelatin-alginate gels provide references and novel prospects of IPN for the application in the field of food industry.