Structure, rheology, and tribology of date fruit paste procured from different date palm cultivars

Abstract

AbstractDate paste is an intermediate food product from date palm fruit containing valuable nutrients having a great potential as sugar substitute or filler in various food formulations. The study aimed to investigate the physicochemical, rheological, tribological, structural, and thermal characteristics of date paste prepared from five cultivars of date palm (Aseel, Muzawati, Dhakki, Rabai, and Karbalain). Dynamic rheological analysis demonstrated viscoelastic nature of all samples. The elastic modulus (G′) was higher than viscous modulus (G″) for all samples, indicating gel‐like nature. All samples showed the typical Stribeck tribological curves, wherein the friction coefficient in the boundary regime in Dhakki, Muzawati, and Rabai pastes were higher than Karbalain and Aseel samples. The friction coefficient was reduced at mixed regime, enhancing lubrication by prevention of surface contact. Endothermic peaks were observed for all samples wherein peak temperature ranged between 138.49 and 154.13°C. The microstructure properties of date paste samples were similar except Muzawati paste.Practical applicationsRecently, there has been a renewed interest in the date palm fruit in order to make better use of off‐grade fruit as a component in various food preparations such as health foods, baking products, and confectionery. Date paste (processing waste) can be used as alternative to sugar for making several food recipes like cakes, desserts, sweets, biscuits, soups, sauces, and so on. Date paste can also be used in salad dressing to add a distinctive sweet taste. Spread date paste simply on toast or swirl it into morning oatmeal or consume it individually in breakfast to gain more energy during the whole day. It is a preferred ingredient for different diets, such as vegan and paleo diets. The current study describes comprehensive information regarding the rheological behavior, textural, tribological, and phytochemical nature of date fruit paste of top commercial cultivars of date palm from Pakistan. The obtained data may provide a general guideline when considering the use of date paste from different cultivars in food products.