Quality of mini-peeled carrots as affected by genotype, minimal processing and edible coating

Abstract

Minimally processed vegetables provide convenience, fresh characteristics and human health benefits. Some fresh carrots are minimally processed by abrasive peelers and washed to remove cellular fluids to produce carrot sticks, mini peeled carrots and grated carrots. Shelf life and acceptability of packaged minimally processed carrots is sometimes limited by a white discoloration that develops on abraded surfaces during storage, and poor flavor. This study was undertaken to investigate the effects of genotype, minimal processing and edible coating treatment on quality of mini-peeled carrots. Genotypic variations in total terpenoids, sugars, phenolics, total carotenoids and sensory attributes were observed (P>0.05). Among experimental hybrids evaluated TX30129 had the highest sugar and carotenoid levels. White surface discoloration on mini-peeled carrots was noted 7 days after processing. Total sugars, sucrose, total carotenoids and volatile terpenoid levels decreased during storage. Total soluble phenolics increased up to 14 days storage and then declined. Edible coating treatment effectively retarded white surface discoloration without diminishing microbial or chemical quality of mini-peeled carrots. Sensory scores for fresh carrot flavor, fresh carrot aroma and overall acceptability were higher for coated carrots. An application rate of 0.23-0.49 L/min appeared adequate for protection against surface discoloration and for retention of flavor. Terpenoid and carotene contents declined within 3 days after processing. Edible coating treatment did not affect terpenoid or carotenoid levels during storage. Apparently, Nature SeaTM coating had poor barrier characteristics since volatile terpenoids readily diffused through the coating during storage. Carotene losses during peeling were most likely associated with enzymatic activity or increased exposure to oxygen. Packaging mini-peeled carrots under reduced oxygen conditions may retard carotene loss.