Recent Development on the Chemical Composition and Phenolic Extraction Methods of Apple (Malus domestica) - A Review

Apple (Malus domestica) is a reliable source of nutrients to increase the bioactive compounds intake in the human body. In the market, the development of apple is still growing, not only in the hybridization of new cultivars, but also in the functional food products, based on apple’s bioactive compounds. In this paper, we review the recent studies about the chemical composition of apples, including carbohydrates, proteins, lipids, dietary fibers, minerals, vitamins, phenolics, and other compounds, from various cultivars, grown in different countries or regions. Among the bioactive compounds in apple, the phenolic compounds, including hydroxybenzoic acids, hydroxycinnamic acids, flavanols and their oligo- and polymeric structure, flavonols, dihydrochalcones, and anthocyanins, majorly contribute to beneficial biological impacts. Therefore, the extraction process might be the most critical step to recover all the phenolics from apple and could be used in various food product developments. In this paper, the comparison of conventional and developed phenolic extraction methods is also reviewed in various apple products (flesh, peel, pomace, pulp, etc.). The selection of food grade and green solvents in the optimal phenolic extraction methods could reduce the environmental issues, thus supports sustainability and can be safer for consumers. To sum up, this paper may help the readers, both at general household and industrial levels, to understand the nutritional composition of various apple cultivars from different regions and to select the optimum conditions for apple’s phenolic extraction, based on recent studies.