No abstract

Selenium is an essential element in the human diet. Interestingly, there has been an increased consumption of dietary supplements containing this element in the form of either inorganic or organic compounds. The effect of using selenium as a dietary supplement in yogurt has been evaluated. For this purpose, different concentrations of inorganic Se (ranging from 0.2 to 5000 microg g(-1)) have been added to milk before the fermentation process. Biotransformation of inorganic Se into organic species has been carefully evaluated by ion-exchange, reversed-phase, or size-exclusion chromatography, coupled to inductively coupled plasma mass spectrometry (ICP-MS). Yogurt fermentation in the presence of up to 2 microg g(-1) of Se(IV) produces a complete incorporation of this element into proteins as has been demonstrated applying a dialysis procedure. Analysis by SEC-ICP-MS showed that most of them have a molecular mass in the range of 30-70 kDa. Species determination after enzymatic hydrolysis has allowed the identification of Se-cystine using two different chromatographic systems. The biotransformation process that takes place during yogurt fermentation is very attractive because yogurt can act as a source of selenium supplementation.

No abstract

The chemical modification of starch from physiologically immature bananas (Musa paradisiaca L.) was performed via the in situ polymerization of ϵ‐caprolactone (CL) utilizing ammonium decamolybdate as a catalyst to obtain a starch‐g‐PCL copolymer in one step. The copolymerization conditions were studied by varying the CL/catalyst mass ratio, the reaction temperature, and the reaction time. The final product was characterized using different technical instruments to demonstrate copolymerization. Based on the results, the graft copolymer was successfully synthesized, and the mass yield reached 85.2% at a temperature of 110°C with a DPn(NMR) of 10 and a Mn(NMR) of 1141 Da. The monomer conversion to copolymer followed a power‐law model with a reaction order of 3/2. The thermal properties and crystallinity of the starch and polycaprolactone in the copolymer were affected due to the formation of starch‐g‐PCL clusters.