A Novel Process for the Recovery of Betalains from Unsold Red Beets by Low-Temperature Enzyme-Assisted Extraction

Abstract

Food waste management plays a central role in the circular economy. To our knowledge, only a few studies have investigated the use of unsold fruit and vegetables from supermarkets as a substitute source for the extraction of natural colorants. Thus, the aim of this paper was to suggest a green, tailored protocol that avoids the use of organic solvents for the recovery of betalains from unsold red beets for use as a food colorant. The recovery of such pigments was carried out by a tailored enzymatic mix, blended considering the polysaccharide composition of the beetroot cell wall; thus, it consisted of: cellulase (37%), xylanase (35%), and pectinase (28%). The enzyme-assisted extraction protocol was optimized, and the most suitable conditions (in terms of pigment yield and color attributes) for the recovery of betalains from unsold beets appeared to be: 25 U/g total dose of enzymatic mix, temperature 25 °C, and processing time 240 min.

Natural colorants from vegetable food waste: Recovery, regulatory aspects, and stability—A review

“…EAE has been widely applied by using commercially available enzymes (e.g., cellulase, amylase, and pectinase) (Table 2). Prokopov et al (2017) proved an enhanced recovery yield of carotenoids from tomato peels by an enzymatic mix (cellulase 100 U g −1 and hemicellulase 400 (Jing & Giusti, 2007) Betalains Unsold beetroot Polygalacturonase, Cellulase, Xylanase 11.37-14.67 mg/mL U (Lombardelli et al, 2021a) Dragon fruit Pectinex Ultra SP-L 550 mg/L (Naderi et al, 2010) Red beetroot waste Celluclast 1.5 L, Pectinex Ultra Mash 3.06 mg/g dry basis (Fernando et al, 2021) Chlorophylls Spinach Pectinex Ultra SP-L 50.7 mg TCC/100 g pulp (Özkan & Bilek, 2015) Pandan leaf Pectinex Ultra SP-L 17.82 mg/g fresh weight (Senklang & Anprung, 2010) Abbreviations: GAE, gallic acid equivalents; MGE, malvidin glucoside equivalent; TCC total chlorophyll content.…”

“…They are a group of water‐soluble pigments, deriving from betalamic acid, that give colors to plants of the order Caryophyllales, such as red beets and prickly pears (Strack et al., 2003). They are composed of two main groups: the red‐purple betacyanins and the yellow‐orange betaxanthines (Lombardelli et al., 2021a). The former are the products of the condensation of betalamic acid with cyclo‐dopa, while the latter are derived from the condensation of betalamic acid and amines (Stintzing et al., 2002).…”

“…Recently, Lombardelli et al. (2021a) developed an eco‐friendly approach for the recovery of betalain from unsold beetroot. Vulić et al.…”

“…Lombardelli et al. (2021a) recovered betalain from unsold red‐beets applying a tailored enzymatic mix based on the polysaccharide composition of the red‐beet cell wall. The process was conducted at 25 and 45°C.…”

“…Sharma et al (2021) described in depth the betalains extraction from vegetable waste, such as red dragon fruit peels and prickly pear. Recently, Lombardelli et al (2021a) developed an eco-friendly approach for the recovery of betalain from unsold beetroot. Vulić et al (2014) showed the antioxidant, antiproliferative, and free radical scavenging activities of betalains recovered from beetroot peel and pomace by ultrasound-assisted extraction (UAE).…”