Effects of Different Levels of Gum Arabic, Low Methylated Pectin and Xylan on In Vitro Digestibility of β-Lactoglobulin

Abstract

Plant hydrocolloids used in the food industry to improve texture and stability of food, such as dairy products, can reduce protein digestibility and, consequently, modify the bioavailability of amino acids. We studied the in vitro hydrolysis at 37 degrees C of beta-lactoglobulin (beta-lg) in mixed dispersions containing either gum arabic or low-methylated pectin or xylan at levels of 0, 1, 10, 20, 30, and 50% weight. Proteolysis used either pepsin alone by progressive reduction of pH during proteolysis or pepsin followed by trypsin and chymotrypsin in two different dialysis bags with a molecular weight (MW) cutoff of 1000 or 8000 Da. Results showed that beta-lg was almost resistant to pepsin digestion and that the three plant hydrocolloids inhibited significantly beta-lg digestibility as determined using dialysis bag with a 1000-Da MW cutoff. Among the three polysaccharides used, xylan showed a digestibility decrease greater than that obtained with gum arabic and low-methylated pectin. On the other hand, no significant effect of polysaccharides on the in vitro beta-lg digestibility was detected using the dialysis bag with an 8000 Da MW cutoff. This mainly suggests that peptides with MW in the range 1000 to 8000 Da may interact with polysaccharides more than peptides and proteins with a greater molecular weight to decrease the protein digestibility, and that the nature of the polysaccharides plays a role in the interaction.

Effects of gum arabic, low methoxy pectin and xylan on in vitro digestibility of peanut protein

“…The absence of a difference in N release from protein without polysaccharides through the two dialysis bags was also obtained with b-lactoglobulin, a globulin protein of whey milk (Mou ecoucou et al, 2003), suggesting that proteins were mainly hydrolyzed in to low MW peptides (<1000 Da) so increasing the porosity of the membrane did not greatly change the results. Conversely, the electrophoresis patterns of PPI without polysaccharide showed slight difference between the retentates from the two dialysis bags.…”

Evaluation of protein in vitro digestibility of Palmaria palmata and Gracilaria verrucosa

“…The nature of the polysaccharides plays a major role in the interaction between protein and polysaccharides. In this way, Mouecoucou et al, 2003 and2004, have shown that xylan, arabic gum and pectin prevented hydrolysis of β-lactoglobulin or peanut protein isolate, differently according to their nature.…”

Identification of Proteolytic Bacteria from Thai Traditional Fermented Foods and Their Allergenic Reducing Potentials

“…Of the 2 well‐known proteolytic enzymes, trypsin and chymotrypsin, trypsin specifically cleaves peptide bonds after the N‐terminal of lysine and/or arginine residues, while chymotrypsin specifically cleaves peptide bonds after tyrosine, tryptophan, phenylalanine, leucine, and/or methionine residues (Margoliash and Smith 1962; Mouécoucou and others 2003). The enzyme of B. subtilis DB was found to potentially cleave peptide bonds after the N‐terminal of leucine, glutamine, lysine, threonine, and phenylalanine.…”