Antimicrobial and aromatic edible coating on fresh-cut pineapple preservation / Revestimento comestível antimicrobiano e aromático na conservação de abacaxi minimamente processado

The present research aimed to develop an edible coating incorporated with mint essential oil, evaluate its effectiveness in inhibiting in vitro microbial development, and improve both quality and shelf-life of fresh-cut pineapple. Mint essential oil-containing edible coatings showed in vitro antimicrobial efficiency against Escherichia coli and Salmonella Enteritidis. Titratable acidity, pH, and texture were not affected (P>0.05) by coating or storage time. Mass loss was not higher than 1.0% after the 6th day of storage. No effect of storage time and coating on total soluble solids was observed. Mint essential oil-containing coatings inhibited the growth of yeasts and molds in fresh-cut pineapple. Compared to uncoated and control-coated samples, mint essential oil-containing coatings lessened psychrotrophic bacteria counts throughout storage. Counts of thermotolerant coliforms were not higher than 3.0MPN·g-1 in all treatments, whereas no Salmonella sp. was detected during the 6-day storage. Mint essential oil provided a strong flavor to the fruit, as shown by sensory evaluations.

O objetivo deste trabalho foi desenvolver um revestimento comestível incorporado com óleo essencial de hortelã, bem como avaliar sua eficiência antimicrobiana in vitro e em abacaxi minimamente processado. Revestimentos contendo óleo essencial de hortelã mostraram eficiência antimicrobiana in vitro contra Escherichia coli e Salmonella Enteritidis. O pH, a acidez titulável e a textura não foram afetadas (P>0.05) pelos tratamentos durante o armazenamento. A perda de massa dos abacaxis de todos os tratamentos não ultrapassou 1.0% após 6 dias de armazenamento. O tempo e os diferentes revestimentos não afetaram (P>0,05) o teor de sólidos solúveis totais dos abacaxis. Revestimentos contendo óleo essencial de hortelã foram capazes de inibir o crescimento de fungos e leveduras em abacaxi minimamente processado, quando comparado aos frutos sem revestimento e com revestimento controle. Frutos com revestimento contendo óleo essencial de hortelã apresentaram menor contagem de psicrotróficos no final do armazenamento. A contagem de coliformes termotolerantes foi menor que 3.0NMP·g-1 para todos os tratamentos e não foi detectada presença de Salmonella sp. durante o período de armazenamento. A presença de óleo essencial de hortelã conferiu forte sabor aos abacaxis.

Alternative sanitization methods for minimally processed lettuce in comparison to sodium hypochlorite

Lettuce is a leafy vegetable widely used in industry for minimally processed products, in which the step of sanitization is the crucial moment for ensuring a safe food for consumption. Chlorinated compounds, mainly sodium hypochlorite, are the most used in Brazil, but the formation of trihalomethanes from this sanitizer is a drawback. Then, the search for alternative methods to sodium hypochlorite has been emerging as a matter of great interest. The suitability of chlorine dioxide (60 mg L-1/10 min), peracetic acid (100 mg L-1/15 min) and ozonated water (1.2 mg L-1 /1 min) as alternative sanitizers to sodium hypochlorite (150 mg L-1 free chlorine/15 min) were evaluated. Minimally processed lettuce washed with tap water for 1 min was used as a control. Microbiological analyses were performed in triplicate, before and after sanitization, and at 3, 6, 9 and 12 days of storage at 2 ± 1 ºC with the product packaged on LDPE bags of 60 µm. It was evaluated total coliforms, Escherichia coli, Salmonella spp., psicrotrophic and mesophilic bacteria, yeasts and molds. All samples of minimally processed lettuce showed absence of E. coli and Salmonella spp. The treatments of chlorine dioxide, peracetic acid and ozonated water promoted reduction of 2.5, 1.1 and 0.7 log cycle, respectively, on count of microbial load of minimally processed product and can be used as substitutes for sodium hypochlorite. These alternative compounds promoted a shelf-life of six days to minimally processed lettuce, while the shelf-life with sodium hypochlorite was 12 days.

Activity of enzymes associated with the enzymatic browning of minimally processed potatoes

The purpose of the present study was to evaluate the effect of different potato cultivars and storage temperatures on the specific activity of phenylalanine ammonia-lyase (PAL), polyphenol oxidase (PPO) and peroxidase (POD) in minimally processed potatoes. Potato cultivars Agata, Asterix and Monalisa were selected, washed, peeled, diced, sanitized, centrifuged, vacuum- packed and stored at 5 and 15°C for 9 and 5 days, respectively. There was an increase in the enzymatic activity in all the cultivars stored at 15°C. The cultivars 'Agata' and 'Asterix' stored at 5ºC did not differ significantly between them for the PAL, PPO and POD activities. The PAL, PPO and POD activities were also influenced by the storage temperature. The cultivars Agata and Asterix were more suitable in minimal processing than 'Monalisa', which was more susceptible to oxidative browning.

Efeito do tipo de corte e de sanificantes no escurecimento de pequi minimamente processado / Effect of cutting type and sanitizers on the browning of fresh cut peki fruit

Conduziu-se este trabalho, com o objetivo de avaliar a influência dos sanificantes hipoclorito de sódio (NaClO) e de peróxido de hidrogênio (H2O2) em diferentes concentrações sobre a vida de prateleira de pequi (Caryocar brasilense Cambess.) submetido a dois tipos de processamento mínimo: "caroço fatiado" e "caroço inteiro", e armazenados a 6 ± 1° C e 90 a 95 por cento UR, durante 15 dias. O experimento foi conduzido em delineamento inteiramente casualizado, disposto em um fatorial 2 x 6 x 5, ou seja, 2 tipos de processamento (caroços "fatiados" e "inteiros"), 6 tempos (0h, 3, 6, 9, 12, 15 dias) e 5 tratamentos (controle, NaClO 50 ppm, NaClO 100 ppm, H2O2 4 por cento e H2O2 6 por cento), com 3 repetições. A cada três dias foram realizadas as análises: vitamina C, polifenoloxidase, peroxidase e cor (CIE L*a*b*). O pequi minimamente processado apresentou decréscimo nos teores de vitamina C ao longo do armazenamento. O caroço fatiado mostrou-se com maior atividade da enzima polifenoloxidase em relação ao inteiro. A interação significativa entre o corte, o sanificante e o tempo ocorreu para a variável peroxidase, tendo sido observado para o caroço fatiado tratado com os sanificantes H2O2 4 e 6 por cento maior atividade dessa enzima. Observou-se a redução do valor de L*, durante o armazenamento do pequi minimamente processado, independente do sanificante utilizado, ocasionado pelo escurecimento do produto.

The objective of the present work was to evaluate the influence of the sanitizers sodium hypochlorite (NaClO) 50 and 100 ppm and 4 percent and 6 percent, hydrogen peroxide (H2O2) on the shelf life of fresh cut peki fruit (Caryocar brasilense Cambess.) submitted to two sorts of processing: "sliced stone" and whole stone", stored at 6 ± 1° C and 90 to 95 percent of RH for 15 days. The analyses were performed every three days. The experiment was conducted in a completely randomized design arranged by a 2 x 6 x 5 factorial, i.e. 2 sorts of processing ("sliced and whole stones"), 6 times (0h, 3, 6, 9, 12, 15 days) and 5 treatments (control, 50 ppm NaClO, 100 ppm NaClO, 4 percent H2O2 and 6 percent H2O2 ), with 3 replicates. Every three days, the following analyses were conducted: vitamin C, polyphenoloxidase, peroxidase and color (CIE L*a*b*). The fresh cut peki fruit showed decreases in the contents of vitamin C during storage. The sliced stones showed itself with an increased activity of the enzyme polyphenoloxidase relative the whole one. The significant interaction cutting sanitizer and time was found for peroxidase, the sliced stones and the sanitizers 4 percent and 6 percent H2O2 having promoted the highest activity of that enzyme. Reduced value L* during the storage of fresh cut peki fruit was observed, independent of the used sanitizer, suggesting browning of the product.

Controle do escurecimento enzimático e da firmeza de polpa em pêssegos minimamente processados / Control of enzymatic browning and flesh firmness in fresh-cut peaches

O escurecimento enzimático e o amolecimento são as principais alterações que podem afetar pêssegos minimamente processados (MP). Objetivou-se avaliar a aplicação de L-cisteína (Cis), ácido L-ascórbico (AA) e cloreto de cálcio (CC) no controle do escurecimento enzimático e da perda de firmeza de polpa de pêssegos MP, cv. 'Esmeralda'. Os frutos foram processados e, após o fatiamento, imersos nos tratamentos: (I) água (controle); (II) AA+CC; (III) Cis+CC; e, (IV) Cis+AA+CC. Em seguida, as fatias foram acondicionadas em embalagens rígidas envoltas com filme PVC de 30µm de espessura e armazenadas durante seis dias a 4±1°C e 85±3 por cento UR. As amostras foram avaliadas quanto aos aspectos físico-químicos, enzimáticos e sensoriais a cada dois dias. O tratamento Cis+AA+CC resultou em maiores valores de L* e h°, o que indica ter sido o mais eficaz na prevenção do escurecimento. Os tratamentos com L-cisteína resultaram em menor atividade da polifenoloxidase (PPO) e o tratamento Cis+AA+CC foi o mais efetivo na contenção da atividade da peroxidase (POD), indicando que o melhor desempenho desse tratamento está associado à menor atividade de PPO e POD. A avaliação sensorial indicou que o tratamento Cis+AA+CC foi o mais eficiente, proporcionando a manutenção de características sensoriais aceitáveis aos pêssegos MP, cv. 'Esmeralda'.

The enzymatic browning and firmness loss are the major changes that could affect fresh-cut peaches. The objective was to evaluate the application of L-cysteine (Cis), L-ascorbic acid (AA) and calcium chloride (CC) in the control of browning enzymatic and loss of firmness of minimally processed dried peaches, cv. 'Esmeralda'. The fruits were processed industrially and, after slicing, immersed in treatments: (I) water (control); (II) AA+CC; (III) Cis+CC and (IV) Cis+AA+CC. After, the slices were packed in packages sealed with PVC film 30µm thick and stored for six days at 4±1°C and 85±3 percent UR. The samples were evaluated for their physical-chemical, enzymatic and sensory aspects every two days. Treatment Cis+AA+CC resulted in higher values of L* and h°, which indicates that it was the most effective in browning prevention. Treatments with L-cysteine resulted in lower activity of polyphenoloxidase (PPO) and treatment Cis+AA+CC was the most effective in containing peroxidase (POD) activity, indicating that the best performance for such treatment is associated with lower activity of PPO and POD. The sensory evaluation indicated that the treatment Cis+AA+CC was the most efficient, providing the maintenance of the sensory characteristics acceptable for fresh-cut peaches, cv. 'Esmeralda'.

Atividade respiratória e aspectos microbiológicos de cultivares de batatas minimamente processadas e armazenadas em diferentes temperaturas / Respiratory activity and microbiological aspects of minimally processed potatoes cultivars stored at different temperatures

O presente trabalho teve como objetivo avaliar aspectos fisiológicos e microbiológicos de diferentes cultivares de batatas minimamente processadas. Batatas das cultivares 'Ágata', 'Asterix' e 'Monalisa' foram selecionadas, classificadas, lavadas e descascadas por abrasão, sendo em seguida cortadas em cubos, sanitizadas e centrifugadas. Depois foram colocadas em frascos herméticos e armazenadas a 5, 15 e 25°C. Foram determinadas a atividade respiratória e a produção de etileno logo após o processamento e durante 10 horas. As análises microbiológicas foram realizadas no dia do processamento e após nove, cinco e um dia de conservação, a 5, 15 e 25°C, respectivamente. Observou-se que as batatas 'Asterix' apresentaram maiores taxas respiratórias em relação às cultivares 'Ágata' e 'Monalisa', independentemente da temperatura de armazenamento. Nas temperaturas de 15 e 25oC, as batatas 'Ágata' e 'Monalisa' apresentaram comportamentos semelhantes entre si. As contagens de bactérias psicrotróficas e coliformes totais, para todas as cultivares armazenadas 5oC, mantiveram-se dentro dos limites aceitáveis durante nove dias de armazenamento. Não foram detectados coliformes a 45°C e Salmonella. Ficou evidenciada a eficiência do armazenamento a 5°C no controle da atividade metabólica e na segurança microbiológica de batatas minimamente processadas.

The purpose of the present research was to evaluate physiological and microbiological aspects of different minimally processed potatoes cultivars. Potatoes cultivar 'Agata', 'Asterix' and 'Monalisa' were selected, classified, washed and abrasion peeled before being diced, sanitized and centrifuged. They were then placed in hermetically closed flasks and stored at 5, 15 and 25°C. The respiratory activity and ethylene production were determined immediately after the processing and during 10 hours. Microbiological analyses were carried out on the processing day and after one, five and nine days of storage at 25, 15 and 5oC, respectively. Potatoes cv. 'Asterix' showed the highest respiratory rates when compared to potatoes cultivar 'Agata' and 'Monalisa', regardless of the storage temperature. Potatoes cv. 'Agata' and 'Monalisa' behaved similarly to each other at 15 and 25°C. Psychrotrophic bacteria and total coliforms counts for all cultivars were within acceptable limits at 5oC for nine days of storage. The presence of coliforms at 45°C and Salmonella was not detected. Storage at 5°C was effective to control the metabolic activity and to keep food safety of minimally processed potatoes.

Uso de aditivos químicos para a conservação pós-colheita de banana 'Maçã' minimamente processada / Use of chemical additives for postharvest conservation of fresh cut 'Apple' Banana

Objetivou-se, neste trabalho, estudar o efeito de tratamentos com ácido ascórbico (AA), cloreto de cálcio (CC) e cloridrato de L-cisteína (LC) sobre a qualidade pós-colheita de banana 'Maçã' minimamente processada. Foram testadas as seguintes combinações: 1 (Controle); 2 (AA 1 por cento); 3 (CC 1 por cento); 4 (LC 0,5 por cento); 5 (AA 1 por cento + CC 1 por cento); 6 (AA 1 por cento + LC 0,5 por cento); 7 (CC 1 por cento + LC 0,5 por cento); 8 (AA 1 por cento + CC 1 por cento + LC 0,5 por cento). As bananas foram descascadas, fatiadas e imersas nos tratamentos, acondicionadas em bandejas, que foram envolvidas em filme de PVC 30 µm, e armazenadas a 5 ± 1ºC e 90 ± 3 por cento UR, durante 4 dias. As avaliações ocorreram nos dias 0, 1, 2 e 4. Houve um aumento na perda de massa durante o tempo de armazenamento, menor no tratamento 8 em relação aos demais. A acidez total titulável aumentou linearmente com o tempo em todos os tratamentos. A perda de firmeza foi mais eficientemente contida nas fatias sob os tratamentos com cloreto de cálcio. A formação de uma coloração vermelho-rósea sobre as fatias tratadas com L-cisteína foi observada e evidenciada pelos maiores valores de a*. O valor L* e o índice de escurecimento também foram afetados pelo tratamento com L-cisteína, cujo decréscimo nesses parâmetros de cor foi maior nas fatias não-tratadas, ao longo do tempo. O tratamento de banana 'Maçã' minimamente processada com a combinação AA 1 por cento + CC 1 por cento + LC 0,5 por cento foi eficiente para manutenção da sua qualidade pós-colheita.

This work had the aim of studying the effect of treatments with ascorbic acid (AA), calcium chloride (CC) and L-cysteine hydrochloride (LC) on the postharvest quality of fresh-cut 'Apple' banana. The following combinations were tested: 1 (Control); 2 (AA 1 percent); 3 (CC 1 percent); 4 (LC 0.5 percent); 5 (AA 1 percent + CC 1 percent); 6 (AA 1 percent + LC 0.5 percent); 7 (CC 1 percent + LC 0.5 percent); 8 (AA 1 percent + CC 1 percent + LC 0.5 percent). The bananas were peeled, sliced and immersed into the treatments, conditioned on trays, which were wrapped with 30 µm PVC film, and stored at 5 ± 1ºC and 90 ± 3 percent RH, during 4 days. Evaluations occurred at 0, 1, 2 and 4 days. There was an increase in the mass loss during the storage period, lower in the treatment 8 in relation to the others. Total titratable acidity increased linearly throughout the time in all treatments. The loss of firmness was prevented more efficiently in the treatments with calcium chloride. A pinkish-red color formation on the slices treated with L-cysteine was observed and evidenced by the highest values of a*. The L* value and the browning index were also affected by the treatments containing L-cysteine, whose decrease in these color parameters was higher in the untreated slices throughout the time. The treatment of fresh-cut 'Apple' banana with the combination AA 1 percent + CC 1 percent + LC 0.5 percent was efficient for its postharvest quality maintenance.