DEVELOPMENT OF LACTOBIONIC ACID ENRICHED YOGHURT FOR ENHANCED CALCIUM ABSORPTION
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Date
2023
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Publisher
ICAR-NDRI, KARNAL
Abstract
The current research was aimed to produce lactobionic acid (LBA) enriched yoghurt
using Acetobacter orientalis and lactose oxidase, comparison of the developed yoghurts
with the control yoghurt and validate the calcium absorption enhancing capability of the
LBA-enriched yoghurts using in-vitro and in-vivo rat model. The three different market
yoghurt samples were analysed for the presence of the LBA, but no LBA was found in
those samples. For the development of LBA-enriched yoghurt, initially, the inoculation
level of Acetobacter orientalis (10, 15, 20%) and incubation temperature (27, 30, 33°C)
were optimized and later, the lactose oxidase level (10, 20, 30U) and incubation
temperature (37, 40, 42°C) were optimized based on the maximum LBA production and
sensorial acceptability. Various parameters like pH, acidity, acidification rate, lactose,
lactic acid, LBA concentration and microbial count were analysed during incubation. The
final product was analysed for sensorial acceptability and whey syneresis. From the first
stage, the yoghurt with 20% Acetobacter orientalis inoculation with incubation at
30°C/16h was optimized as this sample had desirable acidity (0.72 %LA), highest LBA
concentration (3.62 mg/100g), best overall sensorial acceptability and least whey
syneresis. Among the yoghurt with lactose oxidase, the yoghurt with 30U LactoYIELD®
addition and incubation at 40°C/8h was optimized as it had highest LBA concentration
(16.88 mg/100g), best overall acceptability and least whey syneresis. In the second stage,
these two optimized yoghurts were compared with the control yoghurt. The physicochemical,
microbiological, rheological, textural, sensorial and microstructure parameters
were analysed. The developed samples were comparable to the control sample, except for
the presence of sweetness in the LBA-enriched yoghurts and increased hardness for the
yoghurt with lactose oxidase. All the yoghurts were acceptable for up to 15 days under
refrigerated storage. The cost of developed yoghurts was slightly higher than the control
yoghurt. From the in-vitro analysis, it could be seen that the calcium bioavailability of the
LBA-enriched yoghurt was significantly higher than the control yoghurt. In-vivo studies
showed that the groups with LBA-enriched yoghurt had a 10-12% higher apparent
digestibility coefficient compared to the control feed groups. The apparent digestibility
coefficient was highest (81.04%) for the yoghurt with lactose oxidase group. From the
organ indices, it can be proven that consumption of LBA had no adverse effect on any
organs. The bone parameters of the groups fed with LBA-enriched yoghurt were better
than the control feed group. Hence based on the above results, it is concluded that LBAenriched
yoghurt could be made using Acetobacter orientalis and lactose oxidase, with
similar properties compared to the control yoghurt and can improve the calcium
bioavailability and bone health upon regular ingestion.