Effect of chill storage and modified atmosphere packaging (MAP) on antioxidant activity, anthocyanins, carotenoids, phenolics and sensory quality of ready-to-eat shredded orange and purple carrots

Ready-to-eat shredded orange and purple carrots, packed in air (control), or in modified atmosphere packaging [MAP; (90%N2 + 5%O2 + 5%CO2 and 95%O2 + 5%CO2)], and stored chilled for up to 13 days, were examined for their antioxidant activity and contents of anthocyanins, carotenoids and phenolics, as well as sensory quality. Total antioxidant activity, carotenoids and phenolics of purple carrots were initially 2.8-, 2.3- and 2.9-fold higher than orange carrots, respectively. Total antioxidant activity remained relatively constant in orange carrots during storage under all treatment conditions, whereas a highly significant decrease (P<0.01) in (95%O2 + 5%CO2)-treated purple carrots was observed. The content of anthocyanin, only found in purple carrots, was decreased slightly during the storage period, and this was particularly significant in the 95%O2 + 5%CO2 treatment. In both orange and purple carrots, loss of total carotenoids occurred in the 95%O2 + 5%CO2 treatment. Total phenolic content of purple carrots increased at a much higher rate during storage than orange carrots. The MAP treatment (90%N2 + 5%O2 + 5%CO2) gave better sensory quality and extended shelf-life for purple carrots (∼2–3 days longer shelf-life than other treatments,) but, no difference was observed for orange carrots. Shredded purple carrot can be stored under 90%N2 + 5%CO2 + 5%O2 treatment for up to 10 days and high nitrogen treatment may be used in maintaining the storage quality of shredded purple carrots. Thus, purple carrots may be used in place of orange carrots to take advantage of their nutraceutical components.