Organic Chemistry, Natural Products and Food Stuffs

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Hydrostatic pressure and heat treatments as abiotic stress to enhance bioactive composition of pineapple (Ananas comosus L.) by-products

Publication . Santos, Diana Isa de Oliveira; Martins, Margarida Moldão; Saraiva, Jorge Manuel Alexandre; Vicente, António Augusto Soares

Abiotic stresses effect [cutting, moderate heat treatments (MHT) and moderate hydrostatic pressures (MHP)] on enzymatic activity [bromelain, phenylalanine ammonia lyase (PAL), polyphenoloxidase (PPO)], total phenolic content (TPC) and antioxidant activity (AAox) of pineapple by-products (shell and core) was studied. Single or combined MHT effect (30±1 °C or 40±1 °C, 10 min) and cutting, followed by storage at 4±1 °C for 24 h or 48 h, was also studied. For the pineapple core, cutting and MHT (40 °C) before storage (24 h) induced a synergistic effect on TPC accumulation (17%) and AAox (4-22%). In pineapple shell, the treatment that most promoted the increase of TPC (14%) and AAox (38-45%) was MHT at 30 °C followed by storage (48 h). Pineapple by-products were subjected to MHP (50-400 MPa, 1-15 min) according to a central composite rotational design. The results indicate that MHP treatments activated bromelain and PAL, reaching maximum activity at 225 MPa, 8 min (additions relatively to raw material: PAL 262%, TPC 36% in pineapple shell and bromelain 350% in pineapple core). The pressurized by-products under optimized conditions were lyophilized and crushed. Characterized functional flours (physicochemical and microbiological, TPC, AAox, bromelain activity and mycotoxins present) were added to meat marinades and yogurts. Meat was evaluated (pH, hardness, marinade yield and color). The results indicated that additions of 10-20 mg tyrosine.100 g−1 meat implied a decrease in pH and hardness (41%) of the meat. Yogurt was studied (sensory analysis, bromelain activity, proteolysis, TPC and AAox). The tasters preferred 20% (w/w) added yogurt. Bromelain activity and TPC bioaccessibility were higher in yogurt with a pressurized pineapple core compared to the raw material. The results allow us to conclude that pineapple by-products respond positively to abiotic stresses

2021Tese de doutoramento

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Fundação para a Ciência e a Tecnologia

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6817 - DCRRNI ID

Número da atribuição

UID/QUI/00062/2019