Application of Antioxidants and Edible Starch Coating to Reduce Browning of Minimally-Processed Cassava

Abstract

-This study aimed to evaluate the quality of minimally-processed cassava treated with antioxidants and a starch-based edible coating. Cassava roots were washed, cooled, immersed in cold water, peeled and then cut. Root pieces were then immersed in a chloride solution, centrifuged, and subsequently immersed in either a starch suspension (3%), a solution containing antioxidants (3% citric acid and 3% ascorbic acid), or in both the coating and antioxidant solutions. Coated root pieces were dried at 18 ± 2°C for 1 hour, then packaged into polypropylene bags (150 g per pack) and kept at 5 ± 2°C for 15 days, and assessed every 3 days. A completely randomized design was used in a 4 × 6 factorial consisting of the treatment (control, coating, antioxidant, or coating and antioxidant) and the storage period (0, 3 6, 9, 12 or 15 days), with three replicates in each group. The pH, blackened area and peroxidase and polyphenol oxidase activities of the cassava was reduced in treatments containing antioxidants and the scores of visual analysis and phenolic content were higher. Therefore, treatment with antioxidants was effective for reducing browning in minimallyprocessed cassava, retaining the quality of cassava pieces stored for 15 days at 5 ± 2°C. The combination of antioxidants and the edible coating showed no improvement compared to treatment with antioxidants alone.Keywords: Manihot esculenta Crantz. Physiological changes. Postharvest. ESCURECIMENTO EM MANDIOCA DE MESA MINIMAMENTE PROCESSADA COM USO DE ANTIOXIDANTES E REVESTIMENTO DE AMIDORESUMO -Objetivou-se avaliar a qualidade de mandioca de mesa minimamente processada com o uso de antioxidantes e revestimento comestível a base de amido. Raízes de mandioca de mesa foram lavadas, resfriadas, imersas em água fria, cortadas e descascadas. Os pedaços foram imersos em solução clorada, centrifugados e imersos em suspensão de amido (3%) ou em solução contendo antioxidantes (ácido cítrico 3% e ácido ascórbico 3%) ou em ambos (revestimento + antioxidantes). Os pedaços contendo revestimento foram secos em sala climatizada a 18 ± 2 °C por 1 hora. Os pedaços foram embalados em polipropileno, contendo 150 g por embalagem, e mantidos a 5 ± 2 °C por 15 dias, com avaliações a cada três dias. Foi utilizado o DIC, em esquema fatorial 4 x 6 [controle, revestimento, antioxidantes e revestimento + antioxidantes x dias de conservação (0; 3 6; 9; 12 e 15 dias)] com 3 repetições. Verificou-se que os valores de pH, área escurecida e as atividades da peroxidase e polifenoloxidase foram menores e as notas da análise visual e o teor de fenólicos totais foram superiores nos tratamentos contendo antioxidantes. O uso dos antioxidantes foi eficiente na redução do escurecimento em mandioca de mesa minimamente processada, mantendo os pedaços com qualidade por 15 dias a 5 ± 2 ºC e a associação de antioxidantes e revestimento comestível não apresentou melhorias em comparação aos antioxidantes isolados. Palavras-chave:Manihot esculenta Crantz. Alterações fisiológicas. Pós-colheita.

Association of preharvest management with oxidative protection and enzymatic browning in minimally processed cassava

“…Interestingly, in our study, all averages up to 15 days were above grade 3 (Figure 1a, b), which is the limit of commercial acceptance according to Coelho et al (2017). This suggests that all recommended procedures for maintaining the quality of minimally processed cassava, for example, a cold chain, the use of sharp knives and appropriate packaging and temperatures for storage (Silva, Soares, & Geraldine, 2003), were correctly conducted.…”

“…In addition, the presence of a fermented odor and whitening of the pieces, related to starch precipitation, was recorded. These characteristics were subjectively scored on a scale ranging from 1 to 5, based on that described by Coelho, Andrade, Mélo Neto, Ferreira-Silva, and Simões (2017). Each piece received a score, and the average value was calculated for each sample.…”

“…In this study, the authors reviewed superficially the effects of pruning, which increases the sugar/starch ratio and limits scopoletin accumulation, and furthermore they suggested that PPD should be evaluated at different harvest ages, indicating that this factor affects the postharvest quality of the roots. Andrade et al (2017) demonstrated that at high harvest ages, the freshly harvested roots had lower enzyme activities and lower metabolite contents related to oxidative protection, such as SOD, CAT, and phenolics. However, how the age of harvesting and other management issues in the field affect PPD in the conservation of minimally processed cassava roots, remains to be determined.…”

“…Factors related to cultivation that can easily be modified, such as the harvest age and population density, promote changes in plants, both in morphology and postharvest quality attributes (Andrade et al, 2017;Leskovar, Agehara, Yoo, & Pascual-Seva, 2012;Simões et al, 2010). Recently, some field strategies have been reported to delay PPD in unprocessed cassava roots (Zainuddin et al, 2018).…”

Changes in the oxidative metabolism of cassava (Manihot esculenta Crantz) roots associated with cultivation managements

“…Couto (2013) evidenced that root harvest time can modify the activity of PPO and POD enzymes, which act in the plant defense against pathogens attack of and in response to wounding. These enzymes appear to be some of the main involved in browning in cassava roots (Rickard, 1985;Freire et al, 2015;Coelho et al, 2017). Additionaly, there are divergences in the PPD tolerance of different cassava genotypes harvested at 180 (Zidenga et al, 2012), 300 (Canto et al, 2013), and 330 DAP (Venturini, 2015).…”