BIOACTIVE COMPOUNDS IN FRESH-CUT PRODUCES AS AFFECTED BY ABIOTIC STRESSES

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Heat shock and UV-C abiotic stress treatments as alternative tools to promote fresh-cut carrot quality and shelf-life

Publication . Alegria, Carla Sofia Marques de; Martins, Margarida Moldão; Abreu, Marta Maria Nogueira; Cisneros-Zevallos, Luis

Abiotic stress treatments, heat shock (HS_100 ºC/45 s) and UV-C (0.1-5 kJ.m-2), and two passive modified atmosphere packaging conditions were evaluated under the hurdle concept as alternative approaches to the standard processing of fresh-cut carrot (FCC). The significant phenolic accumulation, via phenylalanine-ammonia lyase activation, showed to be independent on key factors contributing to raw material bioactivity, cultivar and crop season, but dependent on treatments intensity (HS_[100 ºC/45 s], UV-C_[2.5 kJ.m-2]) and on oxygen availability (>2%). The low decontamination efficiency of UV-C_[2.5 kJ.m-2] as single hurdle was similar (p>0.05) to that of sodium hypochlorite (<1 Log10 cycle in aerobic mesophilic microflora) and was responsible for FCC early sensorial rejection (<7 days), regardless packaging conditions. The simultaneous effects on microbiological control and reduced metabolic rates yielded by HS_[100 ºC/45 s] significantly contributed to the preservation of FCC sensorial quality allowing the full recovery (100%) of raw materials’ phenolic levels (≥5 days, 5 ºC), with no synergic effects in the combination with UV-C, resulting in FCC shelf-life extension by two-fold (14 days, 5 ºC) when using a bi-oriented polypropylene micro-perforated film

2015Doctoral thesis

Open access

Multi-Target Alternative Approaches to Promoting Fresh-Cut Carrots’ Bioactive and Fresh-like Quality

Publication . Alegria, Carla; Gonçalves, Elsa; Moldão, Margarida; Abreu, Marta

Fresh-cut fruits and vegetables, as near-fresh foods, are a quick and easy solution to a healthy and balanced diet. The rapid degradation of nutritional and sensory quality during the processing and storage of a product is critical and plant-type-dependent. The introduction of disruptive technological solutions in fresh-cut processing, which could maintain fresh-like quality with less environmental impact, is an emerging research concept. The application of abiotic stress treatments (heat shock and UV-C) induces metabolic responses and microbial effects in plant tissues, potentially slowing down several quality senescence pathways. The previously selected combined and single effects of heat shock (100 C/45 s; in the whole root) and UV-C (2.5 kJ/m2) treatments and two packaging conditions (oriented polypropylene (OPP) vs. micro-perforated OPP films) on controlling critical degradation pathways of fresh-cut carrots and on promoting bioactive and sensory quality during storage (5 C, 14 days) were studied. Among the tested combinations, synergistic effects on the quality retention of fresh-cut carrots were only attained for applying heat shock associated with micro-perforated OPP film packaging. Its effects on reducing (3.3 Log10 CFU/g) the initial contamination and controlling microbiological spoilage (counts below the threshold limit of 7.5 Log10 CFU/g), increasing the bioactive content (38% and 72% in total phenolic content and chlorogenic acid, respectively), and preserving fresh quality attributes prove to be a viable alternative technology for shredded carrot processing

2022Journal article

Open access