Background: Papaya and strawberry contain a wide array of nutrients that contribute to human health; however, availability of these fruits is limited due to their short shelf lives and seasonal nature. In this study, the effect of alternative techniques including ultra high temperature (UHT, 20-135 °C, 1-3 s) and irradiation (0-10 kGy) on carotenoid concentration, antioxidant capacity and changes to pulp structure using transmission electron microscopy were determined for papaya and strawberry nectars.
Results: UHT had moderate effects on antioxidant capacity, but the greatest overall release of carotenoids from the pulp matrix (34.2%, 6.26%, 8.31%; β-cryptoxanthin, β-carotene, and lycopene, respectively). Irradiation resulted in the greatest increase in antioxidant capacity [19.22 to 24.32 µmol Trolox equivalents kg(-1) (papaya), 190.51 to 287.68 µmol Trolox equivalents kg(-1) (strawberry)], with moderate effects on carotenoid concentration.
Conclusion: This research demonstrates that decreases in nutrient value and antioxidant capacity can result from processing, but that regeneration of these losses can be seen corresponding to the apparent breakdown of pulp structure. © 2015 Society of Chemical Industry.
Keywords: ORAC; TEM; antioxidant; carotenoid; nutrient value; pulp structure breakdown.
© 2015 Society of Chemical Industry.