Efeitos de diferentes condições de tratamento térmico e de temperatura de armazenagem em congelação na qualidade de polpas de hortofrutícolas

Mestrado em Engenharia Alimentar - Qualidade e Segurança Alimentar - Instituto Superior de AgronomiaThe present research aimed to evaluate the effects of pasteurization, through the development of degradation kinetics (80 °C to 98 °C in time intervals of 0.5 to 25 min), on the physical-chemical, biochemical, microbiological and sensory parameters of two pulps. The studied pulps were formulated by a mix of pear and pineapple (P_Amarela) and of pear, strawberry, beetroot and lemon juice (P_Vermelha). The thermal binomials were optimized taking into account the achieved peroxidase activity inhibition (≥80%) and microbial load reduction (≥1 Log cycle) just after processing. The binominals that allowed pulps stabilization according to the mentioned criteria with minimal impact on the sensory quality were of 90 °C/5min and 90 °C/4min for P_Amarela and P_Vermelha, respectively. The effects of freezing storage (70 days, -18 °C and -5 °C) were also evaluated on pasteurized and non-pasteurized pulps. During storage, the low temperature allowed to further reduce the achieved initial microbial reduction while maintaining the peroxidase inhibition and sensory characteristics. Storage at -18 °C proved to be more efficient to the maintenance of the evaluated quality parameters of both pasteurized and non-pasteurized pulp formulations. The studied preservation methods, pasteurization and freezing, showed a synergic effect contributing to pulps high sensory acceptabilit