Survivability and Population Dynamics of Lactic Acid Bacteria (LAB) in Probioticated Sapota Juice (Achras sapota L.) and their Influence on Physicochemical Properties

Background: Sapota (Achras sapota L. or Manilkara zapota L.) is one of the major fruit crops grown in subtropical countries and it contains sugars, acids, protein, phenolics carotenoids, ascorbic acid, minerals and vitamins. Growing of lactic acid bacteria in fruit juices for health benefits and improving the nutritional and sensory attributes of the fruit juice is becoming more prominent in the present days. In recent years, consumer preference for non dairy food products has increased especially for lactose intolerance people. The present study is aimed to develop probioticated sapota fruit juice using probiotic bacteria like Lactobacillus plantarum, Lactobacillus bulgaricus, Lactobacillus acidophilus, Lactobacillus casei. Methods: Sapota fruit juice was prepared and inoculated with four different species of proven probiotic lactic acid bacteria (Lactobacillus plantarum, Lactobacillus bulgaricus, Lactobacillus acidophilus and Lactobacillus casei) and incubated at 30oC and 37oC for 72 hours. Population dynamics of lactic acid bacteria and their impact on physicochemical properties of probiotic sapota juice during fermentation at two different temperatures were studied. Sensory evaluation was also studied to know the overall acceptability of the probiotic fruit juice. Result: The pH decreased and titratable acidity (TA) increased in all probiotic sapota juice samples incubated at 30oC and 37oC for 72 hours and the maximum titratable acidity was recorded by T4 (Lactobacillus plantarum) followed by T1 (L. acidophilus). All the three carbohydrates like glucose, fructose and sucrose present in sapota juice samples were utilized by the lactic acid bacteria during fermentation. Total phenolic concentration in the samples increased during fermentation. Viable cell counts in both samples kept at 30oC and 37oC gradually increased from 0 to 48 hours and then decreased. Sensory evaluation was conducted randomly for all the samples and no significant difference was recorded.

Optimization of enzymatic clarification of sapota (Achras sapota L.) juice using response surface methodology

Aim: The present study aimed to develop enzymatic clarified sapota (Achras sapota L.) juice beverage under optimized conditions for future scale up. Methodology: In this study, the ripened sapota fruits PKM 1 variety were ground to pulp and pulp was mixed with 0.05-0.15% pectinase enzyme and incubated at 35oC-45oC for 30-120 min. After incubation period the enzyme was deactivated by placing the pulp in warm water bath at 90oC for 3 min. Optimal enzymatic clarified juice was produced by pectinase enzyme by response surface methodology. Results: The absorbance values decreased with increasing incubation time at fixed temperature. Incubation time showed a significant and p<0.05 negative effect on L* value at linear terms. At fixed temperature, the L* value increased with increasing enzyme concentration. Significant regression models proved that the changes in clarity, juice yield and colour (L*values) when compared to the independent variables demonstrated, coefficient of determination, R2 greater than 0.8. Interpretation: Optimization conditions like minimum clarity, maximum juice yield and maximum color (L* value) can be applied in the production of sapota juice for commercial use.

Biosynthesis and Characterisation of Silver Nanoparticles using Leaf Extract of Achras sapota l. for its Antimicrobial Activity

<p>Nanotechnology is a field that is rapidly growing, making an impact in all spheres of human life. In the current study, silver nanoparticles were synthesized using the ethanolic leaf extract of <em>Achras sapota. </em>Characterization was carried out using UV-Visible spectroscopy, FTIR, XRD, SEM and TEM. The formation of AgNPs was confirmed through UV-Visible spectroscopy by the colour change. Based on the XRD pattern, the crystalline property of the AgNPs was established. The functional group present in the ethanolic leaf extract of <em>Achras sapota</em> is responsible for the reduction of the Ag⁺ ion which was studied through FTIR. From the SEM and TEM analysis, it was found that the formed nanoparticles are spherical in shape and nano in size. The biosynthesized AgNPs was evaluated for its antimicrobial activity against gram positive bacteria (<em>S. aureus and L. bacillus</em>) and gram negative bacteria (<em>E. coli and P. aeruginosa</em>) using disc diffusion for preliminary screening of antimicrobial activity and dilution method for evaluation of antibacterial effectiveness and effect of silver nanoparticles on bacterial growth and it was found to exhibit potential antimicrobial activity. The biosynthesized AgNPs was found to be efficient in terms of reaction time as well as stability, eco-friendly and cost effective.</p>