# Thermal Properties of Ultrasound-Extracted Okra Mucilage
## 1 Introduction  
Currently, many micro- and macro-components that can be extracted from plants are of great interest to different consumer demands. Among these components, polysaccharides are of great interest because of their biological and pharmacological properties, including antitumor, antiviral, antioxidant, and anti-inflammatory activities. Okra (_Abelmoschus esculentus_) referred to as lady's finger is considered both a vegetable and a medicinal crop and is typically grown in tropical, subtropical, and temperate regions around the globe; it is a flowering plant that is widely cultivated and consumed as a vegetable in many parts of the world [1]. Okra is a flowering plant that belongs to the mallow family. Unripe and tender fruits are consumed as vegetables. Okra is rich in protein, fat, carbohydrates, calcium, phosphorus, iron, and numerous vitamins, all of which provide numerous health benefits such as reducing fatigue and quickly restoring physicalstrength. Okra has various applications in the food, pharmaceutical, and biomedical sectors. Okra mucilage is a thick liquid extracted from okra pods that contains random coil polysaccharides, such as galactose, rhamnose, and galacturonic acid [2; 3; 4; 5]. Currently, studies are being carried out on the development of different extraction methods because of the time-consuming nature and limited efficiency of classical extraction methods. Various techniques, including hot water extraction, enzyme-assisted extraction, microwave-assisted extraction, ultrasound-assisted extraction, and subcritical water extraction, are commonly employed for the extraction of bioactive polysaccharides from okra [6; 7; 8]. One of the extraction methods that has been studied and used in the last few decades is ultrasound-assisted extraction. The utilization of ultrasonic-assisted extraction (UAE) is a popular, non-thermal technique that is employed to extract bioactive polysaccharides from a diverse range of sources, such as okra polysaccharides, seaweed-derived alginates and carrageenanans, and brewer's-yeast-derived \(\beta\)-glucan. UAE operates by utilizing mechanical, thermal, and cavitation phenomena [6; 9; 10; 11]. Ultrasound-assisted extraction is the simplest and most versatile method for cell disruption and extraction. With this method, it is possible to increase the extraction efficiency and yield and shorten the extraction time by exposing the material to ultrasonic sound waves. It has been shown to have a number of beneficial effects, including making the product lighter, improving its emulsifying properties, antioxidant activity, and reducing impurities [12]. The thermal properties of food include the specific heat and enthalpy, thermal conductivity, diffusivity, and heat penetration coefficient. Knowledge of the thermal properties, such as the specific heat and thermal conductivity, is necessary for effective thermal design [13]. Heat conduction is the predominant type of heat transfer that occurs during the processing and storage of food and agricultural products. According to reports, the preliminary structural characteristics and thermal stability of bioactive polysaccharides extracted utilizing a variety of extraction procedures remained mostly unaltered [6; 14]. In this study, the mucilage part of okra vegetables, which has an important role in terms of food and health, was obtained by ultrasound-assisted extraction, which is an environmentally friendly and economical extraction method, and the structural and thermal properties of this polysaccharide extract were determined by chemical and physicochemical methods. One of the important objectives of our study is to determine the effects of ultrasound extraction technology at different solid/solvent ratios and times on the thermal stability and molecular characterization of the products. The utilitarian goal of obtaining and characterizing the mucilage of okra under different extraction conditions and determining its thermal properties could be to explore and utilize the mucilage for various practical applications.