Document Type : Full paper (Original article)
Authors
1
Graduated from Dairy Science College, Karnataka Veterinary, Animal and Fisheries Sciences University, Bangalore, 560024, India
2
Department of Dairy Technology, Dairy Science College, Karnataka Veterinary, Animal and Fisheries Sciences University, Bangalore, 560024, India
3
Department of Dairy Microbiology, Dairy Science College, Karnataka Veterinary, Animal and Fisheries Sciences University, Bangalore, 560024, India
4
Ph.D. Student in Poultry Nutrition, Department of Poultry Science, Veterinary College, Karnataka Veterinary, Animal and Fisheries Sciences University, Bangalore, 560024, India
Abstract
Yoghurt is a unique fermented dairy product, consumed throughout the world and the trend of
consumption is increasing due to its unique health benefits. Yoghurt mix is often supplemented with MSNF
(milk solids-non-fat), it may contain as much as 5.7% unhydrolysed lactose. Lactose can be hydrolysed with
an enzyme lactase. Deficiency of lactase in lactose-intolerant persons leads to gastrointestinal disorders; such
consumers may find it difficult to consume lactose unhydrolysed yoghurt. The production of lactose
hydrolysed yoghurt by pre-hydrolysing of lactose in the yoghurt mix by enzymatic hydrolysis of lactose was
studied using standard materials and methods. Among the different levels of enzyme examined (0.12 to
0.56% of yoghurt mix with increment of 0.04% at each level), 0.16, 0.32 and 0.52% were found suitable to
hydrolyse 50, 70 and 90% lactose in the yoghurt mix, respectively. Lactose hydrolysed yoghurt (LHY)
prepared from 70% followed by 50% lactose hydrolysed mix (LHM) had significantly higher scores for body
and texture, flavour and overall acceptability than control (P<0.05). However, 90% LHY secured
significantly lower scores for sensory scores (P<0.05) and lactose hydrolysis in mix had no effect on colour
and appearance of yoghurt at all levels of hydrolysis. Lactose hydrolysis reduced the setting time by 30-45
min over control (210 min) (P<0.05). The curd strength was checked by measuring penetration (mm/5sec)
using a cone penetrometer. The yoghurt from 50, 70 and 90% LHM had shown significantly increased
penetration of 280, 325 and 395 mm/5sec as compared to control (195 mm/5sec) and the amount of whey
separation increased as the degree of lactose hydrolysis increased (P<0.05).
Keywords
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