Almond By-Products: Valorization for Sustainability and Competitiveness of the Industry

Abstract

The search for waste minimization and the valorization of by-products are key practices for good management and improved sustainability in the food industry. The production of almonds generates a large amount of waste, most of which is not used. Until now, almonds have been used for their high nutritional value as food, especially almond meat. The other remaining parts (skin, shell, hulls, etc.) are still little explored, even though they have been used as fuel by burning or as livestock feed. However, interest in these by-products has been increasing as they possess beneficial properties (caused mainly by polyphenols and unsaturated fatty acids) and can be used as new ingredients for the food, cosmetic, and pharmaceutical industries. Therefore, it is important to explore almond’s valorization of by-products for the development of new added-value products that would contribute to the reduction of environmental impact and an improvement in the sustainability and competitiveness of the almond industry.

Study of Phenolic Compounds and Antioxidant Capacity of Spanish Almonds

“…Isorhamentin- The sum of flavan-3-ols represents 62-85% of the total detected flavonoids with values between 14.14 and 29.93 mg/100 g fw. Barral-Martinez et al [44] assembled lower results in whole almonds of flavan-3-ols (1.27-5.13 mg/100 g fw) compared to those of our study (14.33-29.93 mg/100 g fw). However, they obtained higher results of flavanols (11.3-23.1 mg/100 g fw).…”

Almond Hull as a Functional Ingredient of Bread: Effects on Physico-Chemical, Nutritional, and Consumer Acceptability Properties

“…Acid detergent fibre varies from 20.6 to 35.2%, neutral detergent fibre from 10.0 to 15.0%, cellulose from 20.6 to 35.2%, and crude lignin ranges from 7.5 to 15.6% [2]. Generally, this byproduct is used as livestock feed or fuel material [2], but it is a rich source of triterpenoids (betulinic, urosolic, and oleanolic acids), flavonol glycosides, phenolic acids (caffeic, ferulic, p-coumaric, and synaptic acids), catechin, protocatechuic acid, vanillic acid, and other polyphenolic compounds; therefore, it may be an interesting source of natural antioxidants and other bioactive compounds [3][4][5][6][7]. The total polyphenolic content is comprised of between 35.9 and 166.7 mg GAE/g extract [4,6].…”

“…Generally, this byproduct is used as livestock feed or fuel material [2], but it is a rich source of triterpenoids (betulinic, urosolic, and oleanolic acids), flavonol glycosides, phenolic acids (caffeic, ferulic, p-coumaric, and synaptic acids), catechin, protocatechuic acid, vanillic acid, and other polyphenolic compounds; therefore, it may be an interesting source of natural antioxidants and other bioactive compounds [3][4][5][6][7]. The total polyphenolic content is comprised of between 35.9 and 166.7 mg GAE/g extract [4,6]. When incorporated into the diet, almond hulls (AHs) not only reduce colon cancer risk in rats, increase high-density lipoprotein cholesterol levels, and reduce LDL cholesterol levels in humans [4,6], but also reduce DNA scission and metal ion chelation activities [4,5].…”

“…The total polyphenolic content is comprised of between 35.9 and 166.7 mg GAE/g extract [4,6]. When incorporated into the diet, almond hulls (AHs) not only reduce colon cancer risk in rats, increase high-density lipoprotein cholesterol levels, and reduce LDL cholesterol levels in humans [4,6], but also reduce DNA scission and metal ion chelation activities [4,5].…”

Adsorption of Polyphenols from Almond Blanching Water by Macroporous Resin

“…Subsequently, two by-products have received much attention: almond skins and blanching water, the latter being considered a great candidate to be a sustainable source of phytochemicals, such as flavonoids, tannins, and phenolic acids [2][3][4] Given the current legislation, blanching water must be disposed of as special waste, while the integuments are occasionally fed to animals as fodder [5]. Hence, the exploitation of almond by-products must be integrated into a sustainability context, outlining strategies to establish a circular economy around the almond industry [6].…”