The possible hypocholesterolaemic properties of milk and fermented milk products have been investigated in groups of albino rats given a basal diet, basal diet plus cholesterol, and basal diet plus cholesterol together with whole milk or standard or bifidus yogurt. The yogurts were fortified with skim milk powder, condensed whey or lactose-hydrolysed condensed whey. After 30 d, triacylglycerols, total cholesterol, HDL-cholesterol and LDL-cholesterol were measured in serum. Whole milk and ordinary yogurt had no hypocholesterolaemic effect, but standard yogurt containing lactose-hydrolysed condensed whey and all bifidus yogurts lowered serum cholesterol. In general, yogurts changed HDL-cholesterol little, but tended to raise triacylglycerols. There was marked lowering of LDL-cholesterol in rats given either type of yogurt fortified with whey proteins. This study has demonstrated in a rat model that bifidus yogurts and yogurts fortified with whey proteins can reduce total and LDL-cholesterol, and suggests that if they have the same effect in human subjects they have potential value in cholesterol-lowering diets.

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Calcium enriched herbal ice cream was developed using calcium gluconate (CG) as calcium source, Bacopa monniera whole plant extract (BME) is an herb containing saponins. Ice cream was prepared by incorporating CG and BME together. Preliminarily the range of CG and BME levels were fixed as 50-250 mg/100 mL and 10-50 mg/100 mL of ice cream mix respectively. Response surface methodology (RSM) was used to optimize the levels of two ingredients (CG and BME). Central Composite Rotatable Design using two variables and five responses comprising of sensory attributes was used for computation of optimized solution. All the responses fitted well into quadratic equation with R 2 [ 0.60. The optimum levels of CG and BME are 217.34 mg/100 mL and 10 mg/ 100 mL for preparation of experimental ice cream. RSM recommended with 87% acceptability for the optimum levels of CG and BME. Product is prepared with optimized solution and subjected to sensory evaluation. Keywords Calcium gluconate Á Bacopa monniera extract Á RSM Á CCRD Á Optimum levels Á Sensory analysis Abbreviations CG Calcium gluconate BM Bacopa monniera BME Bacopa monniera whole plant extract RSM Response surface methodology CCRD Central composite rotary design SNF Solid non fat

Aims: To isolate, identify and characterize thermoduric psychrotrophic bacteria from locally available market samples of pasteurized milk. Study Design: Market samples of pasteurized milk were collected, subjected to laboratory pasteurization and thermoduric psychrotrophic bacteria were enumerated after 10 days of storage at 7ºC.The isolates obtained were identified by 16S rRNA sequencing and subsequent blasting. The isolates were characterized in terms of haemolytic, lipolytic and proteolytic activities. Selected isolates were also assessed for their decimal reduction time at 63ºC.          Place and Duration of Study: Verghese Kurien Institute of Dairy and Food Technology,   (Formerly College of Dairy Science and Technology), Mannuthy, Thrissur, Kerala between September, 2019 to March, 2021. Methodology: A total of 42 market samples of pasteurized milk belonging to seven different brands were assessed for their thermoduric psychrotrophic bacterial population. The thermoduric psychrotrophic bacterial isolates were identified by 16S rRNA sequencing and the sequences obtained were searched with the NCBI BLAST program (http://www.ncbi.nlm.nih.gov) for their closest relatives/reference strains with a homology of over or equal to 99 per cent. Haemolytic, proteolytic and lipolytic activities of the isolates  were determined by  streaking  them on blood agar, skim milk agar (SMA) and tributyrin agar respectively and  grading them based on the presence or absence  of zone of clearance around the colonies developed. Decimal reduction time at 63ºC of two selected isolates was also determined. Results: Six thermoduric psychrotrophic bacteria were isolated from the 42 market samples of pasteurized milk i.e., only 14.3 % of tested samples had thermoduric psychrotrophic bacterial population. 16S rRNA sequencing and subsequent blasting identified the isolates as Aeromonas caviae, Moraxella osloensis, Delftia tsuruhatensis, Staphylococcus arlettae and two strains of Carnobacterium maltaromaticum. On assessing the haemolytic activity of the isolates, A.caviae DMV01 exhibited α haemolytic activity whereas Staphylococcus arlettae DMV02, M. osloensis DMV03, C. maltaromaticum DMV05 and C. maltaromaticum DMV06 exhibited ϒ haemolytic activities.  A. caviae DMV01 was found to be lipolytic and the two Carnobacterium strains exhibited proteolytic activities. Staphylococcus arlettae DMV02 was found to be both proteolytic and lipolytic. Aeromonas caviae DMV01 exhibited D63 value of 4 minutes 38 seconds whereas for Moraxella osloensis DMV03 it was 25 minutes 18 seconds. Conclusion:  Exhibition of heat resistance by microorganisms capable of low temperature growth presents quite a challenging situation in terms of quality assurance and shelf life extension of pasteurized milk. So it is high time that dairy industry takes up initiatives to remain updated with the changes happening in pasteurized milk microflora in order to address the challenges such microorganisms may pose in future.

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