TY - JOUR
T1 - In situ Inactivation of Polyphenol Oxidase in Mamey Fruit (Pouteria sapota) by Microwave Treatment
AU - Palma-Orozco, Gisela
AU - Sampedro, José G.
AU - Ortiz-Moreno, Alicia
AU - Nájera, Hugo
PY - 2012/4
Y1 - 2012/4
N2 - Polyphenol oxidase (PPO) is the enzyme responsible for quality loss in most fruits and vegetables. Quality loss is mainly because of oxidative chemical reactions which generate the darkening of tissues. Mamey fruit (Pouteria sapota) after harvesting suffers a rapid quality decay trough activation of PPO. However, PPO may be inactivated in situ by chemical or thermal treatment. In food processing, microwave treatment (MT) has been used recently as an alternative for PPO inactivation. In this study, it was observed that mamey fruit pulp subjected to a gently MT resulted in a higher PPO activity as the generated heat induced in situ the increase in PPO activity. In contrast, PPO was completely inactivated after long MT by using a high microwave power. Temperature in mamey pulp after MT reached a maximum of 79 °C; although PPO was active up to 60 °C. PPO was completely inactivated when conventional blanching treatment was performed but required a higher temperature (92 °C/300 s). The optimum energy intensity (E opt) for PPO inactivation by MT was 0.51 kJ/g or 937 W/165 s. Under this condition, the remaining PPO activity was inversely proportional to energy intensity (E). Interestingly, MT resulted in a negligible damage in microstructure of mamey pulp, although blanching treatment resulted in large damaging effects on tissue organization and shape. Therefore, MT is proposed as an effective way to completely inactivate PPO without causing any significant damage to fruit tissues and shape; as preservation of color, flavor, and taste would be favored.
AB - Polyphenol oxidase (PPO) is the enzyme responsible for quality loss in most fruits and vegetables. Quality loss is mainly because of oxidative chemical reactions which generate the darkening of tissues. Mamey fruit (Pouteria sapota) after harvesting suffers a rapid quality decay trough activation of PPO. However, PPO may be inactivated in situ by chemical or thermal treatment. In food processing, microwave treatment (MT) has been used recently as an alternative for PPO inactivation. In this study, it was observed that mamey fruit pulp subjected to a gently MT resulted in a higher PPO activity as the generated heat induced in situ the increase in PPO activity. In contrast, PPO was completely inactivated after long MT by using a high microwave power. Temperature in mamey pulp after MT reached a maximum of 79 °C; although PPO was active up to 60 °C. PPO was completely inactivated when conventional blanching treatment was performed but required a higher temperature (92 °C/300 s). The optimum energy intensity (E opt) for PPO inactivation by MT was 0.51 kJ/g or 937 W/165 s. Under this condition, the remaining PPO activity was inversely proportional to energy intensity (E). Interestingly, MT resulted in a negligible damage in microstructure of mamey pulp, although blanching treatment resulted in large damaging effects on tissue organization and shape. Therefore, MT is proposed as an effective way to completely inactivate PPO without causing any significant damage to fruit tissues and shape; as preservation of color, flavor, and taste would be favored.
KW - Blanching treatment
KW - Mamey
KW - Microstructural analysis
KW - Microwave treatment
KW - Polyphenol oxidase
UR - http://www.scopus.com/inward/record.url?scp=84859982607&partnerID=8YFLogxK
U2 - 10.1111/j.1750-3841.2012.02632.x
DO - 10.1111/j.1750-3841.2012.02632.x
M3 - Artículo
C2 - 22515234
SN - 0022-1147
VL - 77
SP - C359-C365
JO - Journal of Food Science
JF - Journal of Food Science
IS - 4
ER -