Monosaccharides and myo-Inositol in Commercial Milks

Abstract

Monosaccharides (galactose, glucose, tagatose, 3-deoxypentulose, N-acetylglucosamine, and N-acetylgalactosamine) and myo-inositol were determined by gas chromatography in different types of market milk (pasteurized, dried, UHT, and in-container sterilized). Glucose, myo-inositol, and N-acetylhexosamine concentrations were similar to those previously found in raw milk and showed no variations due to sample type. Sterilized milk samples were characterized by the presence of tagatose and 3-deoxypentulose and, thus, could be clearly distinguished from UHT samples. The galactose level, which was found to be higher in the samples submitted to stronger thermal treatment, seems to be also a useful indicator for milk classification. Keywords: Monosaccharides; milk classification

Quantification of prebiotics in commercial infant formulas

“…Regarding to fructose, only three samples showed contents higher than 0.1 g/100 g, probably due to the presence of free fructose in the products with added FOS. The galactose content was higher than those found by Morales et al (2004) and similar to those obtained by Troyano, Villamiel, Olano, Sanz, and Martinez-Castro (1996) in commercial sterilized milks. Myo-inositol, a polyalcohol that may play a significant role in the prevention of bronchopulmonary dysplasia and retinopathy in premature infants (Hallman, Saugstad, Porreco, Epstein, & Gluck, 1985), was present in all IFs at concentrations significantly higher than those reported for Spanish commercial milks (Troyano et al, 1996), but similar to the found by Woollard, Macfadzean, Indyk, McMahon, and Christiansen (2014).…”

“…The galactose content was higher than those found by Morales et al (2004) and similar to those obtained by Troyano, Villamiel, Olano, Sanz, and Martinez-Castro (1996) in commercial sterilized milks. Myo-inositol, a polyalcohol that may play a significant role in the prevention of bronchopulmonary dysplasia and retinopathy in premature infants (Hallman, Saugstad, Porreco, Epstein, & Gluck, 1985), was present in all IFs at concentrations significantly higher than those reported for Spanish commercial milks (Troyano et al, 1996), but similar to the found by Woollard, Macfadzean, Indyk, McMahon, and Christiansen (2014). As expected, with the exception of the lactose-free IFs, lactose was the main carbohydrate in all studied products, with amounts varying between 19.2 and 70.1 g/100 g. Maltose was found in most of the analysed IFs in a range from 0.2 to 7 g/100 g. This compound is usually not added as ingredient in IFs and its presence may be related to the partial hydrolysis of the added maltodextrins during processing.…”

Stability of oligosaccharides derived from lactulose during the processing of milk and apple juice

“…The levels of myo-inositol, Nacetyl-glucosamine, N-acetyl-galactosamine and lactose remained constant in the heated milk samples, in agreement with the data from Troyano, Villamiel, Olano, Sanz, and Martinez-Castro (1996). The amount of galactose and lactulose increased significantly with the intensity of heat treatment of milk without OsLu, since it is well known that during the heating, lactose is isomerized to lactulose which is subsequently degraded to galactose and saccharinic acids (Troyano et al, 1996). In the case of milk with OsLu, the significant increase of lactulose content was accompanied by a notable but not significant increase in the concentration of galactose, probably due to a decrease in the pH of the milk after the addition of OsLu.…”

“…Table 2 shows the quantitative data of all carbohydrates analyzed in samples of milk before and after heat treatment with and without the addition of OsLu, as well as those of the corresponding phosphate buffer. The levels of myo-inositol, Nacetyl-glucosamine, N-acetyl-galactosamine and lactose remained constant in the heated milk samples, in agreement with the data from Troyano, Villamiel, Olano, Sanz, and Martinez-Castro (1996). The amount of galactose and lactulose increased significantly with the intensity of heat treatment of milk without OsLu, since it is well known that during the heating, lactose is isomerized to lactulose which is subsequently degraded to galactose and saccharinic acids (Troyano et al, 1996).…”

Advances in Fractionation and Analysis of Milk Carbohydrates

“…Analysis of free carbohydrates in milk and milk products by GC-MS has been described by Reineccius et al [106]. In this study, free carbohydrates (galactose, glucose, and lactose) in milk products, i.e., milk, cream, and cheeses, were isolated by dialysis, converted to trimethylsilyl ethers, and then analyzed by GC-MS. Troyano et al [107,108] developed a GC method for the analysis of free monosaccharides in raw and market milk samples. Valero et al [109] determined the amount of lactulose formed in pasteurized milk by GC of the TMS derivatives of the free sugar, besides monosaccharides were also determined.…”