Apple by-products as source of bioactive substances to be exploited in nutraceutical and cosmetic formulations

Apples are one of the most consumed fruits worldwide. A large part of the crop is destined to transformed food products like juice, cider or jam, generating a high volume of by-products known as apple pomace, that represents about 25 % of the fresh fruit [1]. The use of this material has evident economic and environmental advantages. Nowadays, apple pomace is applied in several fields [2], but it is far from being used in its full potential, considering its possible application in food, pharmaceutical and cosmetic industry. In fact, most bioactive compounds in apple are found in peel and seeds, resulting to be more concentrated in pomace than in whole fruits. The aim of this study was to investigate the content of bioactive substances that contribute to make this waste material a valuable source for new functional products. To this purpose, we investigated the the fatty acids composition and the squalene content in peel and seeds of ancient apple cultivars from Marche region (Italy) and in commercial apple varieties. Squalene is in fact known to exert several beneficial effects, such as antioxidant and drug-delivery activities or skin care uses [3]. The results indicated that seeds contain a squalene content in the wide range 1.7-24.7 mg/100 g of fresh sample. Apple peel, instead, could be a valuable source of oil with an optimal n-6/n-3 ratio (in the range 1.5-7.6). The obtained values are close to the ideal n-6/n-3 ratio (4/1-6/1) [4] making this oil interesting for new nutraceutical formulations. [1]. Bhushan S, Kalia K, Sharma M, Singh B, Ahuja PS. Processing of apple pomace for bioactive molecules. Crit. Rev. in Biotech., 2008; 28: 285–96. [2]. Barreira JCM, Arraibi AA, Ferreira ICFR. Bioactive and functional compounds in apple pomace from juice and cider manufacturing: potential use in dermal formulations. Trends in Food Sci. and Tech. 2019; 90: 76-87. [3]. Reddy LH, Couvreur P. Squalene: A natural triterpene for use in disease management and therapy. Adv.Drug Del. Rev. 2009; 61(15): 1412–26. [4]. Simopoulos AP, Leaf A, Salem Jr N. Workshop on the essentiality of and recommended dietary intakes for omega-6 and omega-3 fatty acids. J. Am. Coll. Nutr. 1999;18 (5):487–9.