Effects of enzymatic lactose hydrolysis on thermal markers in lactose-free UHT milk

Author(s)

de Oliveira Neves, Leandra Natalia ^[1] ; Leal de Oliveira, Marcone Augusto ^[1]

Affiliation

^[1] Univ Fed Juiz de Fora, Dept Chem, BR-36036330 Juiz De Fora, MG - Brazil

• Document type: Journal article
• Source: JOURNAL OF FOOD SCIENCE AND TECHNOLOGY-MYSORE; v. 57, n. 9 JUN 2020.
• Web of Science Citations: 0

Abstract

Lactose-free products are more susceptible to chemical and physical modifications during heating and storage, due to the release of glucose and galactose during enzymatic processing, both more reactive than lactose. The present study demonstrates the effect of enzymatic lactose hydrolysis on 5-hydroxymethylfurfural (HMF), whey protein nitrogen index (WPNI) and lactulose used as thermal markers for UHT milk process monitoring. Six milk leading brands which provided regular and lactose-free UHT milk were selected, giving a total of 12 UHT milk samples analyzed in authentic duplicates. All lactose-free samples showed high levels of HMF index (42.15 mu mol L-1, against 13.11 mu mol L-1 for regular samples) and low lactulose contents (13.03 mg 100 mL(-1), against 35.59 mg 100 mL(-1) of regular ones). High variations in HMF (55-85%) and lactulose (42-91%) intra-brand analysis indicated that both markers are influenced by the lactose hydrolysis process. The paired t test indicated there was no difference among WPNI indexes of regular and lactose-free milks suggesting that this thermal marker is suitable to infer about heat damage in lactose-free dairy matrices. (AU)

• FAPESP's process: 14/50867-3 - INCT 2014: National Institute of Science and Technology in Bioanalysis
• Grantee: Marco Aurelio Zezzi Arruda
• Support Opportunities: Research Projects - Thematic Grants