CURD FROM NANDINI GOOD LIFE MILK WITH 42% PALMITIC ACID???!
Curd or yogurt is a fermented product obtained from milk through the addition of bacterial cultures (Lactobacillus delbrueckii subsp. bulgaricus and Streptococcus thermophilus). These cultures ferment milk sugar, lactose to lactic acid giving the product its texture and characteristic tart flavor. Probiotic cultures of some other lactobacilli and bifidobacteria are also sometimes added to the curd/yogurt to give the product health benefits. Traditionally, curd/yogurt is also prepared in many households using a little of the previous day’s curd as an inoculum.
A customer walked into Ramaiah Advanced Testing Laboratory (RATL) with a yogurt sample that he had prepared using Nandini Good Life (Karnataka Milk Federation, Bengaluru) milk, which is a UHT treated milk with 3.5% fat. He had followed his habitual preparation steps, but with this particular batch, he got a yogurt that had the usual yogurt aroma, but unusual texture. There was no observable syneresis (separation of whey) nor characteristic body (coagulum). The yogurt was also not easily scoopable. He requested a test for adulteration based on his hypothesis that natural curd made from pure milk could never have this consistency or “thickness”.
Based on the ingredients of packaged milk, our scientists decided to check for presence of starch and fat-replacers as possible adulterants in the milk which could have a bearing on the yogurt texture and appearance.
Testing for starch in the Wet Chemistry section of RATL yielded a negative result, indicating that starch was not present. However, an advanced fatty acid profile test by GC-FID of the yogurt sample indicated abnormally high levels of palmitic acid as compared to data reported in standard literature based on the fundamental assumption that milk fat in any form should not show a wide variance in the ratio of percentages of individual fatty acids. Abnormally high levels of palmitic acid is generally indicative of the presence of vegetable fat (vanaspati). The question, however, remains, “Could high levels of palmitic acid cause this unusual consistency or “thickness”??
This sample was submitted by Mr. Pradeep on May 20, 2017. Contact information: 28, 16th Cross, 6th Main, RMV II Stage, Bengaluru 560 094. Cell: +91 889 252 6468