Synthesis and Characterization of a Potential Prebiotic Trisaccharide from Cheese Whey Permeate and Sucrose by <i>Leuconostoc mesenteroides</i> Dextransucrase

The production of new bioactive oligosaccharides is currently garnering much attention for their potential use as functional ingredients. This work addresses the enzymatic synthesis and NMR structural characterization of 2-α-d-glucopyranosyl-lactose derived from sucrose:lactose and sucrose:cheese whey permeate mixtures by using a <i>Leuconostoc mesenteroides</i> B-512F dextransucrase. The effect of synthesis conditions, including concentration of substrates, molar ratio of donor/acceptor, enzyme concentration, reaction time, and temperature, on the formation of transfer products is evaluated. Results indicated that cheese whey permeate is a suitable material for the synthesis of 2-α-d-glucopyranosyl-lactose, giving rise to yields around 50% (in weight respect to the initial amount of lactose) under the optimum reaction conditions. According to its structure, this trisaccharide is an excellent candidate for a new prebiotic ingredient, due to the reported high resistance of α-(1→2) linkages to the digestive enzymes in humans and animals, as well as to its potential selective stimulation of beneficial bacteria in the large intestine mainly attributed to the two linked glucose units located at the reducing end that reflects the disaccharide kojibiose (2-α-d-glucopyranosyl-d-glucose). These findings could contribute to broadening the use of important agricultural raw materials, such as sucrose or cheese whey permeates, as renewable substrates for enzymatic synthesis of oligosaccharides of nutritional interest

Table_1_High-Temperature Short-Time Pasteurization System for Donor Milk in a Human Milk Bank Setting.docx

<p>Donor milk is the best alternative for the feeding of preterm newborns when mother's own milk is unavailable. For safety reasons, it is usually pasteurized by the Holder method (62.5°C for 30 min). Holder pasteurization results in a microbiological safe product but impairs the activity of many biologically active compounds such as immunoglobulins, enzymes, cytokines, growth factors, hormones or oxidative stress markers. High-temperature short-time (HTST) pasteurization has been proposed as an alternative for a better preservation of some of the biological components of human milk although, at present, there is no equipment available to perform this treatment under the current conditions of a human milk bank. In this work, the specific needs of a human milk bank setting were considered to design an HTST equipment for the continuous and adaptable (time-temperature combination) processing of donor milk. Microbiological quality, activity of indicator enzymes and indices for thermal damage of milk were evaluated before and after HTST treatment of 14 batches of donor milk using different temperature and time combinations and compared to the results obtained after Holder pasteurization. The HTST system has accurate and simple operation, allows the pasteurization of variable amounts of donor milk and reduces processing time and labor force. HTST processing at 72°C for, at least, 10 s efficiently destroyed all vegetative forms of microorganisms present initially in raw donor milk although sporulated Bacillus sp. survived this treatment. Alkaline phosphatase was completely destroyed after HTST processing at 72 and 75°C, but γ-glutamil transpeptidase showed higher thermoresistance. Furosine concentrations in HTST-treated donor milk were lower than after Holder pasteurization and lactulose content for HTST-treated donor milk was below the detection limit of analytical method (10 mg/L). In conclusion, processing of donor milk at 72°C for at least 10 s in this HTST system allows to achieve the microbiological safety objectives established in the milk bank while having a lower impact regarding the heat damage of the milk.</p

Intestinal Anti-inflammatory Effects of Oligosaccharides Derived from Lactulose in the Trinitrobenzenesulfonic Acid Model of Rat Colitis

Intestinal microbiota modulation is becoming an interesting approach to manage inflammatory bowel disease and can be achieved by the administration of prebiotics. Previous studies showed the intestinal anti-inflammatory effects of the prebiotic lactulose. The aim of the present study was to test the preventative effects of oligosaccharides derived from lactulose with prebiotic properties (OsLu) in the trinitrobenzenesulfonic acid model of rat colitis and compare them with those of lactulose. Both treatments modified bacterial profile in intestinal contents, increasing the bifidobacteria and lactobacilli counts and up-regulating the production of short-chain fatty acids, although OsLu generated a larger amount. OsLu also inhibited to a greater extent different pro-inflammatory markers such as interleukins (IL) 1, 6, 12, and 23 and chemokines (MCP-1 and CINC-1). However, both prebiotics equally restored colonic epithelial integrity, evaluated both with a histological score (OsLu, 9.8 ± 2.2; and lactulose, 12.1 ± 2.1, vs colitic control, 27.3 ± 3.3) and by measuring several key proteins of the mucosal barrier (MUC-2, MUC-3, and TTF-3). OsLu effect was also associated with an inhibition of iNOS expression and a reduction of Th17 cell activity in the inflamed tissue that facilitated the intestinal mucosa barrier recovery. In conclusion, OsLu showed a better anti-inflammatory profile than lactulose in this model of experimental colitis