Browsing by Author "Bhutkar, Sharayu"
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- Application of ultrasound treatments in the processing and production of high-quality and safe-to-drink kiwi juicePublication . Bhutkar, Sharayu; Brandão, Teresa R. S.; Silva, Cristina L. M.; Miller, Fátima A.This study explores the potential of thermosonication as an alternative to traditional heat treatments, such as pasteurization, in the processing of fruit juices. Conventional methods often lead to undesirable quality changes in fruit juices, whereas thermosonication offers promising results regarding microbial inactivation and quality preservation. This work focused on the inactivation kinetics of Listeria innocua 2030c, a surrogate for pathogenic L. monocytogenes, in kiwifruit juice using thermosonication at 45 °C, 50 °C, and 55 °C. These treatments were compared with equivalent heat treatments. Quality attributes of the juice were also evaluated to assess process efficiency. Survival data of L. innocua were fitted with the Weibull model, estimating first decimal reduction times (δ) and shape parameters (n). The results reveal temperature and process dependencies on δ, while n remains mostly temperature and treatment independent. Thermosonication outperforms heat treatment, achieving higher L. innocua reductions while retaining quality attributes like pH, soluble solid content, and total phenolics and chlorophylls. Thermosonication at 55 °C stands out, providing a 6.2-log-cycle reduction in just 3 min with superior quality retention. These findings highlight the synergistic effect of temperature and ultrasound, making mild heat processes feasible while enhancing product quality. Thermosonication, particularly at 55 °C, emerges as an effective alternative to traditional thermal treatments for fruit juices, offering improved microbial safety without compromising product quality.
- Impact of thermosonication on kiwi juice qualityPublication . Silva, Cristina L. M.; Bhutkar, Sharayu; Brandão, Teresa R. S.; Miller, Fátima A.
- Impact of thermosonication on kiwi juice qualityPublication . Silva, Cristina L. M.; Bhutkar, Sharayu; Brandão, Teresa R. S.; Miller, Fátima A.Traditional heat treatments such as pasteurization are usually used in fruit juice preservation. However, due to undesirable quality changes, industries seek other processing technologies that can retain the fruit juices' quality. This study aims to develop a high quality and safe-to-drink kiwi (Actinidia deliciosa cv. Hayward) juice throughout the application of thermosonication treatments (TS). Listeria innocua (a surrogate of the pathogenic L. monocytogenes) was used as a safety indicator. pH, SSC, colour, cloud value, total phenolics, total chlorophylls, and minerals were evaluated as quality parameters. TS was carried out with an ultrasound homogenizer at a constant frequency of 20 kHz, 80% amplitude and discontinued pulsation (10s on, 5s off). The juice samples were submitted to TS at 45, 50 and 55°C for 15, 10 and 3 minutes, respectively. Thermal treatments (HT) were performed at the same temperatures for 60, 25 and 10 minutes. Juices' quality and safety were evaluated before and after treatments. All the treatments fulfil the FDA recommendation of 5-log microbial reduction. Most of the quality parameters were retained after both processes. These results proved that a mild heat process could be applied to fruit juices, allowing the obtention of a safe and improved final product's quality.
- Inactivation kinetics of Listeria innocua in thermosonicated kiwi juicePublication . Bhutkar, Sharayu; Brandão, Teresa R. S.; Silva, Cristina L. M.; Miller, Fátima A.
- Inactivation kinetics of Listeria innocua in thermosonicated kiwi juicePublication . Bhutkar, Sharayu; Brandão, Teresa R. S.; Silva, Cristina L. M.; Miller, Fátima A.In fruit juice processing, traditional heat treatments such as pasteurization are usually used. However, this processing method may often induce undesirable quality changes in fruit juices. Alternatively, thermosonication has been found to have a great potential in microbial inactivation and fruit juices’ quality retention. The objective of this study was to evaluate thermosonication and thermal treatments’ influence on the inactivation kinetics of L. innocua 2030c (a surrogate of the pathogenic Listeria monocytogenes) in kiwifruit (Actinidia deliciosa cv. Hayward) juice. The kiwi peel was manually removed with a peeler to prepare the juice, and then flesh was sliced with a stainless-steel knife. The juice was extracted using a domestic centrifuge. The obtained juice was artificially inoculated with L. innocua subculture (~109 CFU/mL). The kiwi juice was adjusted to a pH of 3.6 by adding Cantaloupe melon (Cucumis melo L. var. reticulatus) juice, a natural component. Thermosonication was carried out in a water bath coupled with an ultrasound homogenizer at a constant frequency of 20 kHz, 80% amplitude and discontinue pulsation (10s on, 5s off). The juice samples were submitted to thermosonication treatments at 45, 50 and 55°C for 15, 10 and 3 minutes, respectively. At the same temperatures, thermal treatments were performed as a control for 60, 25 and 10 minutes. Each experiment was repeated three times. The Weibull model was used to fit all L. innocua log-survival data, based on regression analysis. For thermal treatment at 45°C, the first decimal reduction time (δ) obtained was 23.31 ± 3.51 min, while with thermosonication, the value was significantly reduced to 3.19 ± 0.59 min. The same happens to the other temperatures, with δ for thermal treatments at 50 and 55°C being 5.06 ± 1.73 and 2.50 ± 0.70 min, whereas, with thermosonication, the δ decreased respectively to 1.47 ± 0.59 and 0.46 ± 0.21 min. These results proved the existence of a synergistic effect between temperature and ultrasounds, making it possible to apply mild heat treatment processes and improve the final product’s quality. Since thermosonication treatment was effective in L. innocua inactivation, this technology can be considered a successful alternative to fruit juices’ conventional thermal treatment