Assessment of carrot rejects and wastes for food product development and as a biofuel

Abstract

Carrot (Daucus carota L.) is among the richest source of carotenoids with the highest concentration of β-carotene and a source of vitamin K, fiber, and minerals. β-carotene, also known as a Vitamin A precursor, is a proven anticarcinogen reported for its activity against life-threatening diseases. Of the total production, about 20–30% is separated during primary processing as carrot rejects and waste (CRW). CRW comprised out-graded carrots (separated due to their uniqueness in shape, size, color, or mechanical injury) and processed discards (crowns and tips generated during grading). These are partially utilized towards animal feed and the remaining ends up in landfills. It is estimated that 90,000 lbs of CRW in the landfills released 6988.38 kg of methane, equivalent to 174,709.5 kg of carbon dioxide, causing a detrimental effect on the environment. To reduce the carbon footprint, the study was planned to evaluate the properties (physical, mechanical, carotenoid content, proximate composition, ultimate analysis, high heating value (HHV)) of CRW for its potential utilization in bioenergy and food product development. It was observed that the presence of low carbon (38.55–40.10%), high moisture (86.93–89.35%), and high oxygen (44.66–46.95%) content resulted in low HHV (15.19–15.64 MJ/kg). Hydrothermal liquefaction could be a promising approach to valorize CRW into biofuel. The availability of β-carotene (80–87 μg/g) in CRW samples indicated prospective application in the field of food and nutraceuticals. This study provides a direction for future utilization of CRW, boosting economic gain to processors and producers while reducing the carbon footprint.