OPTIMIZATION OF SPRAY DRYING CONDITIONS FOR PREPARATION OF PROBIOTIC DIRECT VAT SET STARTERS
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Date
2023
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Publisher
ICAR-NDRI, KARNAL
Abstract
Direct vat set (DVS) starters are concentrated form (1011-1014 CFU/g), available in both freezedried
and frozen state. Freeze drying is most commonly used for the production of probiotic
DVS on a commercial scale which is a costly and time-consuming process. On the other hand,
spray drying is a low-cost, high-yield technology being explored in the food sector to prepare
large amounts of dried probiotics. The present study was aimed to select protective agents and
optimize spray drying conditions to prepare DVS starters of probiotic Lactiplantibacillus
plantarum strains. Two probiotic strains i.e. Lactiplantibacillus plantarum CRD7 and Lp.
plantarum HD48 were selected based on their health-promoting features and evaluated for
techno-functional attributes in milk for preparation of dahi. Significance difference (p<0.05)
was observed w.r.t. techno-functional (i.e. curd setting time (14.33±0.02 h), pH (4.26±0.01),
titratable acidity (0.7±0.01 % LA) and total probiotic counts (8.71±0.01 Log CFU/mL), overall
acceptability sensory score (9.0±0.0) and texture profile (firmness 2.30±0.0 N), of probiotic
dahi prepared with Lp. plantarum CRD7 compared to Lp. plantarum HD48 respectively. Based
on better techno functional performance, two Lp. plantarum strains were subjected for heat
challenge experiment using to optimize spray drying parameters i.e. protective agents and inlet
temperature to determine their heat tolerance for the better survivability during spray drying of
probiotic for probiotic DVS powder preparation. Three protective agents i.e. lactose,
maltodextrin and sorbitol were assessed at varied concentrations and temperature combinations
for their heat tolerance to enhance the survivability of selected probiotic Lp. plantarum strains.
Evaluation of probiotic DVS prepared with maltodextrin @ 2.5% concentration showed better
survivability rate exposed to 1 min (95.27±0.03) and 5 min (95.15±0.03) at 55°C compared to
sorbitol and lactose. The cell survivability of selected probiotic Lactobacillus strains was found
to be affected by the type and concentration of the protective agents. Inoculum levels @
0.002% and 0.004% (w/v) of three different spray dried probiotic DVS was optimized for
preparation of dahi. Observations on storage stability of probiotic DVS packed in three
packaging (aluminium laminate, LDPE and EVOH) materials and stored at -20°C and 4°C
exhibited no significant difference in techno-functional performance up to two months of
storage. It is concluded that optimized spray drying conditions for preparation of probiotic DVS
starters of Lp. plantarum CRD7 could be utilized for preparation of health-promoting
fermented dairy foods such as dahi, lassi etc.