Effect of osmotic agents and ultasonication on osmo‐convective drying of sweet lime (Citrus limetta) peel

Abstract

The study was aimed to evaluate the effect of different osmotic agents (sucrose, maltodextrins, and stevia, 50° brix conc.), immersion time (2–8 hr), and ultrasonication treatment (33 KHz, for 2, 5 and 10 min) on water loss, solid gain, weight reduction and subsequent air drying (45°C) behaviour of sweet lime peel. Irrespective of immersion time, the average water loss, solid gain, and weight reduction were observed to be maximum with sucrose as osmotic agent followed by maltodextrins and stevia, respectively. There was only a slight increase in the values of water loss, solid gain, and weight reduction during the ultrasonic‐assisted osmotic dehydration. Sucrose was observed to be the best osmotic agent for osmo‐convective drying of the sweet lime peel. The ultrasound pretreated (10 min, 33 kHz) and sucrose‐osmosed sweet lime peel when subjected to air‐drying, the moisture content was decreased from 28.70 to 1.91%. The values of R2, adjusted R2, and RMSE and residuals analysis indicated that Page model satisfactorily described the drying behavior of sweet lime peel. Practical applications Peels are the main by‐products of sweet lime processing for juice manufacturing. The fruit waste is very rich in pectin and potentially valuable bioactive compounds including antioxidants. The findings of this study may prove instrumental in designing the osmo‐convective drying technology for the sweet lime peel. Since OD can contribute to the retention of useful bioactive compounds and the dried sweet lime peel in its powder form has high concentration of pectin, it can find useful applications in the health industry and food industry especially in processed products such as jams, jellies, or bakery products like biscuit and bread with added functionality and nutraceutical properties. The utilization of osmotically dried sweet lime peel will not only add to the income of sweet lime fruit processors but also provide an avenue for its waste disposal also.

Ultrasonic and osmotic pretreatments followed by convective and vacuum drying of papaya slices

“…Osmotic dehydration encompasses the immersion of fruits in a hypertonic solution to eliminate part of the initial water content of the fruit. The application of US positively affects food processing by improving mass transfer, enhancing shelf life, and effectively assisting thermal treatments 7,8 . The use of US with osmotic solutions as a pretreatment method reduces processing time and moisture content, and enhances the quality and safety of food products 9,10 …”

Hot air convective drying of hog plum fruit (Spondias mombin): effects of physical and edible-oil-aided chemical pretreatments on drying and quality characteristics

“…The moisture ratio during drying of the hog plum fruits at any time; t was calculated using Eq. (1) (Kumari et al, 2020;Kroehnke et al, 2021).…”

Current Applications of Ultrasound in Fruit and Vegetables Osmotic Dehydration Processes

“…The latter can be applied as a single process [11][12][13] or before drying process [14][15][16][17]. However, in recent years, there is a growing interest in new, non-thermal technologies which can be used as a pretreatment before mentioned processes [18][19][20][21] or in assistance to them [22][23][24].…”