Influence of aqueous ozonation on physicochemical properties and incidence of phytopathogens in minimally processed strawberries

Minimally processed strawberries are perishable and susceptible to the development of pathogenic agents, making their post-harvest life limited. Thus, sanitization is a crucial step to ensure the quality of this produce. The objective was to evaluate the effect of treatment with ozone gas dissolved in water on the physicochemical properties and the incidence of pathogens in minimally processed strawberries stored under refrigeration. After minimal processing, “Camino Real” strawberries were submitted to five different treatments: immersion in ozonated water (OW) at three different concentrations (0.2; 0.5; and 1.0 mg L-1) at 10 ºC for 5 min; chlorine sanitization (Sumaveg®) in two steps, at 150 mg L-1 and 5 mg L-1, at 10 ºC for 10 min. The control treatment corresponded to fruits without sanitation. After the treatments, the fruits were stored under refrigeration at 5 ºC and 90% RH and evaluated for 12 days regarding postharvest quality (physical, physicochemical and biochemical), as well as the incidence of diseased fruits (%). The results showed that the sanitization of fruits with ozonized water, regardless of the concentration, favored the quality and health of strawberries during storage compared to fruits subjected to sanitization with chlorinated water and control fruits. Ozonated water treatment is an alternative to traditional sanitization with chlorine, maintaining the physicochemical quality of the minimally processed “Camino Real” strawberries stored under refrigeration

Effect of cellulose microcrystals in starch and chitosan-based films properties

Cellulose microcrystals (CMC) can be used as reinforcing material in the preparation of composite films. This study aimed to evaluate the effect of CMC in starch and chitosan-based films properties. Starch/CMC and Chitosan/CMC composite films were formulated with 1% (w/v) of biopolymer, 0.25% (w/wbiopolymer) glycerol and 0.1% or 0.2% of CMC. The solutions were prepared at 70◦C during 30 min under stirring and submitted to 45 min of ultrasonication. Afterwards were dried in an air-circulating oven at 30◦C for 24 h. The effect of CMC incorporation was evaluated in respect to the surface morphology on a scanning electron microscope (SEM). Solubility was expressed as percentage of the film dry matter solubilized after 24 h immersion in distilled water, and mechanical properties were measured using a texture analyzer following the guidelines of ASTM D 882-10. X-ray diffraction analyses (XRD) were used to evaluate the crystallinity of the samples. SEM micrographs of films with the incorporation of CMC revealed an irregular structure with high heterogeneity and that the roughness of the surface of the films increased for higher concentrations of CMC. Nevertheless, the surface of starch and chitosan films in the absence of CMC are smooth. Regarding to XRD patterns, it was observed that the addition of CMC leads to the presence of reflection peaks at 2θ=22.5° which are related to the cellulose crystalline structure. The values of solubility in water for films with 0.1% and 0.2% of MCM are statistically lower (p<0.05) than for chitosan and starch control films, thus indicating that the presence of CMC reduces the solubility of the film in water. The incorporation of CMC in films decreased the tensile strength values of starch-based films and the elongation at break (p<0.05). Regarding chitosan-based films the incorporation of CMC showed to be effective in increasing the tensile strength values, however leads to a decrease of elongation at break values. Overall, results showed that the incorporation of CMC in chitosan and starch-based films can be used to change the properties of the films and that according to the biopolymer used distinct behaviors can be obtained

MELHORIA NA EFICIÊNCIA DA CLARIFICAÇÃO DE SUCO DE MARACUJÁ PELA COMBINAÇÃO DOS PROCESSOS DE MICROFILTRAÇÃO E ENZIMÁTICO

Este trabalho teve como objetivo a obtenção de suco clarificado de maracujá, utilizando a técnica de microfiltração. Introduziu-se a etapa de tratamento enzimático antes da microfiltração, visando aumentar a eficiência do processo pela redução da viscosidade e do teor de polpa do suco. Foram testadas três diferentes enzimas hidrolíticas em três níveis de concentração. Os resultados não mostraram diferenças significativas quanto ao Brix, pH e acidez das amostras de suco hidrolisado em relação ao suco integral. Observou-se efeito positivo da ação das enzimas na redução da viscosidade e do teor de polpa. A microfiltração foi realizada em sistema de membrana tubular com tamanho médio de poro equivalente a 0,3 µm e pressão transmembrana de 1,5 bar. O suco permeado apresentou-se límpido, isento de polpa e com qualidade e sanidade microbiológica. Tais resultados comprovaram a eficiência da microfiltração para clarificação e estabilização de sucos de frutas. IMPROVEMENT IN THE EFFICIENCY OF PASSION FRUIT JUICE CLARIFICATION BY THE COMBINATION OF MICROFILTRATION AND ENZYMATIC PROCESSES Abstract This work had as objective the obtention of clarified passion fruit juice by using the microfiltration technique. A step of enzymatic treatment was introduced before microfiltration, aiming to enhance process efficiency by reduction of viscosity and pulp content of the juice. Three different hidrolytic enzymes were tested in three concentration levels. The results didnt demonstrate significant differences in Brix, pH and acidity of the hidrolyzed juice samples in relation to the concentrated juice. Positive effect was observed in the action of the enzymes in the reduction of viscosity and pulp content. The microfiltration was realized in a tubular membrane system with average size of the pore equivalent to 0.3 m and transmembrane pressure of 1.5 bar. The permeate juice was clear, free from pulp and with good micribiological quality. Such results proved the efficiency of microfiltration for clarification and stabilization of fruit juices

Efeito do uso de biofilmes nas alterações físicas, químicas e físico-químicas da água de coco verde

A água de coco verde no interior do fruto é estéril, entretanto pode sofrer alterações durante o armazenamento do fruto e durante ou após sua extração, com perda da qualidade nutritiva, alteração no sabor e conseqüente redução do valor comercial. Desta forma, o presente trabalho teve o objetivo de adaptar e desenvolver revestimentos biodegradáveis para prolongar a conservação do coco variedade Anão Verde, propiciando maior tempo para a sua comercialização e para o consumo da água. A água foi extraída de cocos revestidos com biofilmes de quitosana (B1), gelatina + CMC (B2), quitosana + gelatina (B3), CMC (B4) , gelatina (B5) e água [controle] (B6) e armazenados a 12ºC ± 2ºC, UR 80% por 40 dias. Amostras foram retiradas no início e a cada 10 dias para as análises físicas (volume de água e turbidez), fisíco-químicas (sólidos solúveis totais; potencial hidrogeniônico (pH); acidez total titulável); e químicas (glicose, frutose e sacarose; vitamina C total; minerais (P, K, Ca, Mg, Fe, Cu, Zn, Na, Mn); cloreto e nitrogênio total). As características físicas, físico-químicas e químicas foram mais afetadas pelo tempo de armazenamento do que pelos tratamentos com biofilmes. O tempo de armazenamento causou redução no volume de água dos frutos, aumentou a turbidez, reduziu o pH, os teores de sólidos solúveis, de glicose, frutose e vitamina C, aumentou a acidez total titulável, os minerais, mas não teve efeito sobre os teores de sacarose e de alguns minerais como Na e Mn. Os biofilmes e o tempo de armazenamento afetaram a acidez total titulável, os teores de glicose e frutose, a vitamina C, os minerais como o N e Ca, sendo que as águas dos frutos revestidos com quitosana, quitosana + gelatina e gelatina apresentaram poucas alterações destas variáveis com o decorrer do armazenamento, quando comparadas às dos demais tratamentos

Cellulose nanocrystals from grape pomace and their use for the development of starch-based nanocomposite films

Nanocomposite films prepared from starch (ST) in the presence of cellulose nanocrystals (CNCs) was performed using grape pomace as raw material. CNCs were obtained by acid hydrolysis and added to filmogenic solutions (1, 2, 5, 10 and 15 g/100 g of ST). Cellulose, CNCs and Nanocomposites were characterized. Amorphous non-cellulosic materials were removed from the grape pomace presented values for CrI 64% and 71% and yield 12 and 70% in Cellulose and CNCs, respectively. Nanocomposites showed smaller permeability and the addition of 5 to 15% CNCs formed more opaque films and had improved tensile strength and Youngs modulus. The addition of CNCs from 5 to 15% proved to be effective in improving mechanical properties and decreasing water vapor permeability, important characteristics in food packaging materials. This study provided an effective method to obtain CNCs from the agroindustrial waste and open the way to produce high-value starch based nanocomposites.The authors are grateful for financial support provided by FAPERJ - Fundação de Amparo à Pesquisa do Estado do Rio de Janeiro, Brazil (E-26.202749/2018), the National Council for Scientific and Technological Development – CNPq (311936/2018-0), and the Coordenação de Aperfeiçoamento Pessoal do Ensino Superior (CAPES). The support during transmission electron microscopy analyses provided by the LABNANO/CBPF is also very much appreciated.info:eu-repo/semantics/publishedVersio