Effect of thermosonication on pathogenic bacteria, quality attributes and stability of soursop nectar during cold storage

Abstract

2017) Effect of thermosonication on pathogenic bacteria, quality attributes and stability of soursop nectar during cold storage, CyTA -Journal of Food, 15:4, 592-600, ABSTRACTIn this work, the effect of the thermosonication (TS) on the inactivation of Escherichia coli and Staphylococcus aureus in soursop nectar was evaluated, as well as the quality and stability of the nectar during its storage at 4°C. A reduction of 4.5-5 log CFU/mL was achieved with the TS treatment (24 kHz, average temperature of 50-51°C, acoustic energy density of 1.3-1.4 W/mL for 10 min) in both pathogens. Likewise, thermosonicated nectar retained 85% of ascorbic acid, polyphenol oxidase inactivation and microbiological and physicochemical stability during 30 days at 4°C. Sensorially, the thermosonicated nectar was predominantly preferred over a commercial one. TS is a viable alternative to extend the shelf life of minimally processed soursop nectar.Efecto de la termosonicación sobre bacterias patógenas, atributos de calidad y estabilidad de néctar de guanábana durante su almacenamiento en refrigeración RESUMEN En este trabajo se evaluó el efecto de la termosonicación sobre la inactivación de Escherichia coli y Staphyloccocus aureus en néctar de guanábana; así como la calidad y estabilidad del néctar durante su almacenamiento a 4°C. Se logró una reducción de 4,5-5,0 log CFU/mL con el tratamiento de termosonicación (24 kHz, temperatura promedio de 50-51°C, densidad de energía acústica de 1,3-1,4 W/mL, durante 10 min) en ambos patógenos. Del mismo modo, el néctar termosonicado conservó el 85% de ácido ascórbico, la inactivación de polifenol oxidasa y la estabilidad microbiológica y fisicoquímica durante 30 días a 4°C. Sensorialmente, el néctar termosonicado fue predominantemente preferido sobre un néctar comercial. La termosonicación es una alternativa viable para extender la vida útil del néctar de guanábana mínimamente procesado. ARTICLE HISTORY

Effect of storage temperature on the physicochemical, nutritional and microbiological quality of pasteurised soursop (Annona muricata L.) Juice

“…During storage at 10 and 25°C, significant differences in titratable acidity were observed between the control and the stored juice after10 and 2 weeks, respectively. An increase in titratable acidity has also been observed in other fruit juices during storage (Anaya-Esparza et al, 2017;Bull et al, 2004;Chia et al, 2012). The changes in total soluble solids of soursop juice during storage is shown in Figure 4.…”

“…Storage temperature have been observed to have a variable effect on the total phenolic content and total antioxidant capacity of fruit juices. The phenolic content of pineapple juice remained relatively unchanged during 13 weeks of storage (Chia et al, 2012); however, decreases were observed in soursop nectar (Anaya-Esparza et al, 2017). It is possible that the total phenolic content of the soursop juice remained relatively unchanged due to the inactivation of peroxidase during pasteurization (Odriozola-Serrano et al, 2008).…”

Effects of thermosonication process on inactivation ofEscherichia coliandSaccharomyces cerevisiaeand its survival kinetics modeling in khoonphal (Haematocarpus validus) juice to extend its shelf life

“…The lethality of the inoculated microorganisms was assessed as the difference of initial and final count of the logarithm of CFU/ml (log No‐ log N) of the microorganisms at specified treatment condition of PS (92°C/35 s) and TS (50°C/21 min) (Anaya‐Esparza et al, ). The initial population of E. coli and S. cerevisiae in khoonphal juice was 5.183 and 5.934 log CFU/ml, respectively after inoculation in sterilized khoonphal juice (Table ).…”

“…For the determination of the lethality of the microorganisms as a result of the processing, the method described by Anaya‐Esparza et al () was used. Lethality of E. coli was calculated as the difference between the log of colony counts in TSA before and after processing (PS and TS).…”

“…Innovation in preservation technology of fruit juice has been made in recent years to get a maximum yield of all the nutrients present in the fruits and minimal changes in the juice as a result of processing and one such technology for preservation is thermosonication (TS). TS is an emerging hurdle technology, application of ultrasound (US)‐assisted thermal treatment which produces superior quality of fruit juice, maximum retention of phytonutrients, and scoring high consumer acceptance (Anaya‐Esparza et al, ; Jabbar et al, ). An increased thermal treatment ultimately reduced the intensity of cavitation, which enforces the lethal effect combined with the US and these depend mainly on exposure time, pressure, the amplitude of US, and external temperature (Aadil, Zeng, Han, & Sun, ; Adiamo, Ghafoor, Al‐Juhaimi, Babiker, & Mohamed Ahmed, ; Dubrović, Herceg, Jambrak, Badanjak, & Dragović‐Uzelac, ).…”