Comparative study of lactose, galacto-oligosaccharides, volatile profile and physicochemical parameters in reduced-lactose and traditional yogurts

CLAUDIA INÉS VÉNICA; IRMA VERÓNICA WOLF; CARINA VIVIANA BERGAMINI; MARÍA CRISTINA PEROTTI

Congreso; Euro Global Summit and Expo on Food & Beverages; 2015

Lactose intolerance affects about 70% of the world population; itsincidence in South America is very high. Consume of reduced-lactose dairyproducts is recommended for avoid the uncomfortable gastrointestinal symptoms.In the Argentinian market, reduced-lactose fermented milks are not available.The purpose of this study was to compare acidity, lactose andgalacto-oligosaccharides (GOS) concentrations, volatile profile and fat, totalsolids and proteins contents of stirred hydrolyzed yogurts made with added b-galactosidase enzyme, with traditional ones. Yogurts with different fatcontents, sweeteners (aspartame, sucrose) and with and without Lactobacillus acidophilus/inulin, werestudied during storage.Acidityincreased from fresh yogurts to 21 days and was lower in hydrolyzed yogurts thanin traditional ones. Lactose decreased approximately 78% during fermentationfor hydrolyzed products; slight changes were observed during storage. Intraditional products the reduction was 20% during yogurt preparation, whichcontinued decreasing up to 27% at 21 days. Thus, the lactose content was 1.20g/100g and 4.90 g/100g in hydrolyzed and traditional yogurts, respectively, at21 days. The presence of GOS was only detected in the hydrolyzed yogurts(approximately 0.70 g/100g); the values remained constants in some varietieswhile in others they decreased 15% at 21 days. Chemical composition was similarbetween hydrolyzed and traditional yogurts, for each variety. The volatileprofiles were characterized by the predominance of ketones and acids. Overall,acetaldehyde, diacetyl, 2,3-pentanodione, acetoin and volatile acids were themost abundant components. Differences between hydrolyzed and traditional productswere more pronounced at 21 days. The changes observed were dependent on thetype of matrix.