# Valorization of Date Fruit (_Phoenix dactylifera_ L.) Processing Waste and By-Products: A Review
## 2 Types of Date Palm Waste  
The process of harvesting date palm fruit typically results in substantial losses due to fruit falling from the tree prematurely and issues during storage and conditioning. These lost dates are commonly referred to as \"date by-products\" and are considered of low grade due to their inadequate texture, being either too hard or too soft and being contaminated with fungi or infested by insects. Owing to these quality problems and safety risks, these lost dates were generally discarded in the past [16]. Currently, these by-products can be used as animal feed compost, among other purposes, thereby enhancing their value to a certain extent [17].  
The processing of pitted dates generates two major types of waste: the whole date fruits that do not meet quality requirements, and the seeds that are removed during the production process. The seed waste generated from the pitting process of date fruit makes up about 18% of the fruit's total weight [18] (Figure 2). Considering that the world production of dates reached 9.66 million tons in 2021, this would potentially generate over 900,000 tons of date seeds [4]. Indeed, date seeds, previously considered waste, have now gained recognition as a valuable source of fiber and phenolic compounds. Furthermore, they can be converted into products that have added value. Moreover, the oil extracted from date seeds can be converted into value-added products.  
Date seed oil (DSO) can be extracted from date seeds using different methods, including Soxhlet extraction, hydrothermal and ultrasonic-assisted methods, and supercritical and subcritical CO\({}_{2}\) techniques [10; 19]. DSO has numerous applications in the food industry, including its use in cooking, frying, and seasoning. DSO can be used as a replacement for palm olein, a common ingredient in many food products [20]. Previous reports have also mentioned that DSO has been used in margarine production and as an alternative to vegetable oils like corn and sunflower oil in mayonnaise production [19]. DSO can also be used in cosmetic formulations such as body creams, shaving soap, and shampoo [21]. Research has revealed that DSO has properties that help reduce cellular and oxidative rancidity, and it can protect human skin from UV irradiation, making it beneficial for skincare and cosmetic products [21]. In addition, DSO can be utilized in other non-food applications, such as biogas production of deoxygenated hydrocarbons, where DSO can serve as a substrate [22]. DSO's potential applications in both food and non-food industries highlight its versatility and potential value as a by-product of date processing.  
Figure 2: Flowchart of pitted date processing and date juice processing.  
Low-grade dates, unsuitable for direct consumption, can be used to produce other products such as date paste and date juice. Date juice can be further processed to produce date spread, syrup, and liquid sugar or fermented to produce wine, alcohol, and vinegar. Date juice production typically produces date press cake (DPC), a fibrous by-product that remains after the filtration of date juice (Figure 2). This by-product is often bulky in nature and has a high content of moisture and carbohydrates [23]. Date juicing can produce about 17-28% of DPC with high nutritional value, although the conventional use of DPC is still for animal feed or directly discarded [17].