Development and shelf-life determination of pasteurized, microfiltered, lactose hydrolyzed skim milk

Abstract

The segment of the world population showing permanent or temporary lactose intolerance is quite significant. Because milk is a widely consumed food with an high nutritional value, technological alternatives have been sought to overcome this dilemma. Microfiltration combined with pasteurization can not only extend the shelf life of milk but can also maintain the sensory, functional, and nutritional properties of the product. This studied developed a pasteurized, microfiltered, lactose hydrolyzed (delactosed) skim milk (PMLHSM). Hydrolysis was performed using β-galactosidase at a concentration of 0.4mL/L and incubation for approximately 21h at 10±1°C. During these procedures, the degree of hydrolysis obtained (>90%) was accompanied by evaluation of freezing point depression, and the remaining quantity of lactose was confirmed by HPLC. Milk was processed using a microfiltration pilot unit equipped with uniform transmembrane pressure (UTP) ceramic membranes with a mean pore size of 1.4 μm and UTP of 60 kPa. The product was submitted to physicochemical, microbiological, and sensory evaluations, and its shelf life was estimated. Microfiltration reduced the aerobic mesophilic count by more than 4 log cycles. We were able to produce high-quality PMLHSM with a shelf life of 21 to 27d when stored at 5±1°C in terms of sensory analysis and proteolysis index and a shelf life of 50d in regard to total aerobic mesophile count and titratable acidity.

Sustainable alternative for the food industry: converting whey and orange juice into a micro-filtered beverage

“…Several authors have found total bacterial reductions within the range of 4-5 log CFU mL -1 , which are directly related to initial contamination levels, operating parameters, and membrane characteristics (Antunes et al, 2014;Rezzadori et al, 2014). The results of this experiment are consistent with results in many studies, since lower counts were observed for mesophilic aerobic bacteria and yeasts, which were higher in numbers before MF (Table 1).…”

Lactose Hydrolysis in Milk and Dairy Whey Using Microbial β-Galactosidases

“…Horner et al [19], using commercial Kluyveromyces    β -galactosidases in 3, 6, 9, and 12 U/mL concentrations, at 2°C after 48 h of reaction, verified values of approximately 100% lactose hydrolysis efficiency for pasteurized milk. Antunes et al [23] evaluated the physicochemical, microbiological, and sensorial characteristics of delactosed milk using 20 U/mL of the K. lactis    β -galactosidase enzyme at 10°C. Under these conditions, the authors verified a hydrolysis rate of 90% in 21 h of reaction.…”

Recent advances on lactose intolerance: Tolerance thresholds and currently available answers

“…The browning level depends on the hydrolysis percent (Rehman, 2009). In addition, when lactose is hydrolysed, the number of free molecules actually increases, thus raising the amount of soluble substances in the milk, decreasing its freezing point (Antunes et al, 2014). Lactose-hydrolysed milk also presents a higher sweetness due to the lower sweetness of lactose compared with its monosaccharide constituents, glucose and galactose.…”