Characterization of watermelon rind for food industry applications

Abstract

The increasing generation of agro-industrial waste from fruit processing poses serious environmental and economic challenges, necessitating sustainable strategies for waste valorization. Watermelon ( Citrullus lanatus ), widely consumed for its refreshing flesh, generates a substantial amount of rind as a by-product, accounting for nearly 30–38% of the total fruit weight. This book focuses on the comprehensive characterization of watermelon rind and explores its potential utilization as a functional ingredient for food industry applications. The work presents detailed information on the nutritional, physicochemical, functional, and structural properties of watermelon rind powder prepared through controlled drying and milling processes. Proximate analysis highlights the rind as a rich source of dietary fiber, carbohydrates, minerals, and bioactive compounds such as phenolics, flavonoids, and citrulline. Functional properties including bulk density, water and oil absorption capacity, and total soluble solids are evaluated to assess its suitability in food formulations. Advanced structural characterization using Fourier Transform Infrared Spectroscopy (FTIR) and X-Ray Diffraction (XRD) provides insights into the molecular composition and crystalline nature of the rind powder. The book also reviews extensive literature on the nutraceutical potential of watermelon rind, emphasizing its antioxidant, anti-inflammatory, antimicrobial, cardioprotective, and digestive health benefits. Furthermore, various food applications such as bakery products, confectionery items, dietary snacks, pectin extraction, and active packaging materials are discussed to demonstrate its industrial relevance. Overall, this book underscores watermelon rind as an underutilized yet valuable bioresource and advocates its incorporation into food systems to enhance nutritional quality, reduce food waste, and promote sustainable food processing practices.