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Projeto de investigação
Cold high pressure and thermal treatments to promote de novo synthesis of bioactive compounds from pineapple by-products to develop foods with improved functional activities
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Heat treatment and wounding as abiotic stresses to enhance the bioactive composition of pineapple by-products
Publication . Santos, Diana I.; Faria, Diana L.; Lourenço, Sofia C.; Delgado Alves, Vitor; Saraiva, Jorge A.; Vicente, António A.; Moldão, Margarida
Abiotic stress, like heat treatment and wounding, applied to pineapple by-products induce
the accumulation of new compounds and add value. In this work the effect of the individual
or combined application of wounding and heat treatment stresses on total phenolic content, antioxidant
activity through complementary methods (DPPH, FRAP, and ABTS) and enzymatic activity
(bromelain, phenylalanine ammonia lyase (PAL) and polyphenol oxidase) were evaluated. Whole
and wounded pineapple shell and core were dipped in a hot water bath at 30 ± 1 °C or 40 ± 1 °C for
10 min and stored under refrigeration conditions (4 ± 1 °C) for 24 h or 48 h. Results allowed that
pineapple by-products reacted differently to the tested stresses. For the core, the application of
wounding and heat treatment (40 °C) before storage (24 h) induced a synergistic effect on the accumulation
of phenols (increased 17%) and antioxidant activity (4–22%). For the shell samples, the
treatment that most increased the content of phenols (14%) and antioxidant activity (38–45%) was
heat treatment at 30 °C and storage for 48 h. Treatments that positively influenced the content of
phenols and antioxidant activity of the samples did not affect the activity of bromelain or PAL. This
study showed that proper abiotic stresses could increase the functional value of by-products
Optimization of the Effect of Pineapple By-Products Enhanced in Bromelain by Hydrostatic Pressure on the Texture and Overall Quality of Silverside Beef Cut
Publication . Santos, Diana I.; Fraqueza, Maria João; Pissarra, Hugo; Saraiva, Jorge A.; Vicente, António A.; Moldão, Margarida
Dehydrated pineapple by-products enriched in bromelain using a hydrostatic pressure
treatment (225 MPa, 8.5 min) were added in marinades to improve beef properties. The steaks from
the silverside cut (2 +- 0.5 cm thickness and weight 270 +- 50 g), characterized as harder and cheaper,
were immersed in marinades that were added to dehydrated and pressurized pineapple by-products
that corresponded to a bromelain concentration of 0–20 mg tyrosine, 100 g-1 meat, and 0–24 h time,
according to the central composite factorial design matrix. Samples were characterized in terms of
marination yield, pH, color, and histology. Subsequently, samples were cooked in a water-bath (80 ºC,
15 min), stabilized (4 ºC, 24 h), and measured for cooking loss, pH, color, hardness, and histology.
Marinades (12–24 h) and bromelain concentration (10–20 mg tyrosine.100 g-1 meat) reduced pH and
hardness, increased marination yield, and resulted in a lighter color. Although refrigeration was
not an optimal temperature for bromelain activity, meat hardness decreased (41%). Thus, the use of
pineapple by-products in brine allowed for the valorization of lower commercial value steak cuts
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
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Fundação para a Ciência e a Tecnologia
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OE
Número da atribuição
SFRH/BD/109124/2015