Abstract
The aim of this study was to develop an efficient, reliable, and sustainable technology for the recovery of value-added compounds from by-product, in this case, is watermelon rinds. The properties of the watermelon rinds obtained from innovative ultrasoundassisted extraction (UAE) were evaluated. In regard to this, the pectin content, degree of esterification, and galacturonic acid content of the watermelon rind extracts were determined in order to verify the efficiency of the UAE. Initially, the UAE were conducted using two types of acid: citric and hydrochloric. The highest pectin content was obtained using citric acid. Additional UAE was then performed with citric acid at 50, 60, or 70°C for 10, 20, or 30 mins. Both UAE temperature and time significantly influenced the pectin extracts and galacturonic acid. The best findings for a high galacturonic acid content (47.41%) when the watermelon rinds were extracts at 70°C for 20 mins. According to the findings, the extraction process lasted 10 or 20 mins at all temperatures was mainly high-methoxyl pectin, which can form gels under acidic conditions. This suggests that pectins derived from watermelon rinds using UAE may be especially useful as an additive in some confectionery products.
Highlights
Watermelon (Citrullus lanatus) is categorized as an industrial by-product of fresh-cut fruits usually considered under fully utilized
The main limitations for the extraction using mineral acids is requiring special treatments to remove undesirable compounds, the final product can receive the GRAS status (Yapo, 2009). Organic acid such as citric acid has been reported to be similar to those obtained with hydrochloric acid for pectin extraction from apple pomace, cocoa husks, and passion fruit peel
This is in a good agreement with Yang et al (2018), who found the highest pectin yield was obtained with citric acid, in a comparison of several acids, including hydrochloric acid (HCl)
Summary
Watermelon (Citrullus lanatus) is categorized as an industrial by-product of fresh-cut fruits usually considered under fully utilized. The value of watermelon rinds has received increasing attention due to the rich well-spring of functional components such as mineral salts, fat, protein, carotenoid, carbohydrates, vitamins, phytochemicals, cellulose, and citrulline (Quek et al, 2007; Mort et al, 2008; Al-Sayed and Ahmed, 2013; Lakshmipathy et al, 2015). It has been reported, one of the major components of watermelon rind is carbohydrate, some in the form of pectin (Al-Sayed and Ahmed, 2013; Prakash Maran et al, 2014). The recovery of pectin from watermelon rinds might give commercial value to a by-product that is normally discarded
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
