Browsing by Author "M. Balakrishnan"

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    Effect of Pulsed Light Treatment for the Preservation of Coconut Inflorescence Sap
    (2024) V. Vishnu Priya; M. Balakrishnan; Pandiselvam, R.; S. Karthikeyan; Rajkumar, A.; Manikantan, M.R.; K. Gurusamy; P. Preetha
    The present study aims to investigate the impact of pulsed light (PL) treatment on the preservation of coconut inflorescence sap. In order to avoid fermentation of the sap, the freshly collected sap was exposed to various PL process parameters such as the input voltage, which is supplied to the lamp from 500 to 1500 V; the exposure time for treatment ranges from 60 to 180 s; and the distance of the lamp to the treatment chamber, which is selected from 50 to 150 mm. Using Box–Behnken design, the process parameters, such as 1000 V of input voltage, 100 mm of distance and a treatment time of 120 s were optimised based on the physico-chemical and microbial properties. Maximum log reduction of 3.57 log cfu/ml in total plate count and 2.79 log cfu/ml in yeast and mould were observed at the optimum condition. The quality parameters, such as pH and TSS do not have significant effect (p < 0.05) over the treatment. The colour difference value (ΔE) was 0.92, which is mildly noticeable, whereas the turbidity reduced to 42%, total sugars to 6.34% and reducing sugar reduced to 13.58%, with a significant effect (p < 0.05) over the PL treatment. From the results obtained, it was determined that pulsed light technology might be used as a preservation approach for coconut sap with the minimum effect on its quality parameters.
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    Optimization of continuous flow pulsed light system process parameters for microbial inactivation in tender coconut water, pineapple and orange juice
    (2021-09-11) P. Preetha; N. Varadharaju; G. Jeevarathinam; J. Deepa; A. P. Mohan Kumar; M. Balakrishnan; P. Rajkumar; Pandiselvam, R.
    Continuous flow pulsed light (PL) system was designed and fabricated with a residence time of 3.5 s at a flow rate of 100 ml/min to study the effect on microbial quality of the fruit juice. The circuit was designed to deliver pulse energy between 12.6 and 756 J/cm2 with a flash lasted 360 μs at a frequency of three pulses per second. Tender coconut water, pineapple and orange juice was treated with different input voltage (500–1000 V) to the lamp, distance of the lamp exposed to the sample (5–15 cm) and treatment time (15–45 s) to reduce the population of aerobic plate count (APC), yeast and mold. Box–Behnken design (BBD) was used to optimize the PL process parameters. The process condition was optimized based on the microbial reduction rate. The optimized condition was input voltage of 1492, 1499, and 1486 V, distance of 7.6, 10.2, and 5.3 cm, and treatment time of 43 s (12 passes), 44 s (13 passes), and 45 s (13 passes) for tender coconut water, pineapple and orange juice, respectively at the target of five log reduction for APC and four log reduction for Y&M. These results recommend that a continuous flow PL system could improve the microbial safety of the fruit juice. PL is a nonthermal method for inactivating food microbes, extending food's shelf life. For industrial purposes, the batch system is virtually impossible. As a result, continuous flow systems for liquid foods can provide a better way to handle large volumes. The optimized setup was found to achieve a microbial death rate of at least 5 log CFU/ml, consistent with FDA guidelines for fruit juice. The BBD of response surface methodology helps in optimizing the process parameters such as input voltage of the lamp, distance of the PL lamp to treatment tube and treatment time. The resulting mathematical model provides the PL process conditions for designing the equipmentfor different fruit beverages to obtain microbiologically safe products.