Study of the quality of lactose-free milk during storage
Abstract
New food trends have appeared in today's conditions, aimed at fast food establishments. Their assortment includes drinks that include drinking milk. In connection with many consumers with lactase deficiency, drinking lactose-free milk in beverages is proposed. This component is used in small quantities and periodically, provoking its storage in open packaging and the possible risks of reducing its quality. The work aimed to study the quality indicators of drinking lactose-free milk during storage in open packaging under different temperature conditions. For this purpose, lactose-free drinking milk of LLC “Organic Milk”, LLC “Milk Company “Halychyna”, PJSC “Yuriya”, LLC “Lustdorf” was studied. Drinking milk from LLC “Organic Milk”was chosen as the control. The organoleptic and physicochemical indicators of the studied samples in open packaging under storage conditions were investigated: 4 ± 2 ℃ (conditions of a household refrigerator) and 18 ± 2 ℃. The analysis of the investigated milk samples revealed the compliance of their quality indicators with the regulatory documentation. A special feature of lactose-free types of milk is the sweet taste due to the presence of glucose and galactose in their composition. The analysis of sensory properties by the flavor method showed that no negative descriptors regarding color and consistency characteristics were found. There are insignificant values of negative characteristics according to taste descriptors. In the storage process under the first temperature regime, the studied samples of lactose-free milk had normalized organoleptic and physicochemical indicator values for 120 hours. A slight deterioration of the “outside” descriptor at the end of the storage period was detected (up to 0.11 for sample 3). When stored in conditions of 18 ± 2 ℃, the normalized values of the quality indicators of the samples are kept for 48 hours, after which the latent phase of growth and development of microorganisms begins. This causes an increase in titrated acidity and a decrease in sensory properties. Significant changes in titrated acidity were detected for control and 1 sample after 48 hours of storage; for others – at the end of the storage period. An increase in the values of descriptors, “outside”: for control and samples 1 and 2 by 0.11; for sample 3 by 0.17. Thus, the researched types of lactose-free drinking milk have stable quality indicators during storage in open packaging at a temperature of 4 ± 2 ℃.
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