Novel technologies combined with osmotic dehydration for application in the conservation of fruits: an overview / Novas tecnologias combinadas com desidratação osmótica para aplicação na conservação de frutas: uma revisão

ABSTRACT: Osmotic dehydration (OD) is a technique used for the partial removal of water from foodstuff, including fruit and vegetables, with the aim of producing a desiccated product. The process involves placing the material in a hypertonic solution for several hours and allowing water to move from the cell compartment into the solution by osmosis. OD is influenced by various factors such as the concentration and composition of the osmotic solution, the solution temperature, the type of agitation and the time of exposure, as well as the size, shape and compactness of the food material. The main advantages of OD over conventional drying processes are the superior quality of the dried products and the minimization of shrinkage. In recent years, research effort has focused on the combination of OD with other technologies, such as ultrasound, cryogenic freezing with liquid nitrogen, pulsed electric field, gamma radiation and high hydrostatic pressure. The application of these methods prior to or concomitant with OD accelerates mass transfer and reduces the drying rate of fruit and vegetables by increasing the permeability of cell membranes. In this manner, combined processes tend to be more efficient and economical in comparison with conventional OD because they reduce operating times and; consequently, energy consumption. In addition, the dried products generated by such coupled processes typically exhibit improved nutritional and physicochemical characteristics. This review summarizes the basic principles and applications of OD in combination with other methods, with particular emphasis on the production of dried fruits.

RESUMO: A desidratação osmótica (DO) é uma técnica utilizada para remover parcialmente a água dos alimentos, incluindo frutas e vegetais, com vistas a produção de alimentos secos. O processo consiste em colocar o material em uma solução hipertônica por várias horas e deixar a água passar do compartimento celular para a solução por osmose. A DO é influenciada por vários fatores como a concentração e composição da solução osmótica, a temperatura da solução, o tipo de agitação e o tempo de exposição, assim como o tamanho, forma e compactação do material alimentar. As principais vantagens da DO em relação aos processos de secagem convencionais são que ela dá origem a produtos secos de qualidade superior e minimiza o encolhimento. Nos últimos anos, tem-se investigado a combinação da DO com outras tecnologias, tais como ultrassom, congelamento criogênico com nitrogênio líquido, campo elétrico pulsado, radiação gama e alta pressão hidrostática. A aplicação desses métodos antes ou simultaneamente com a DO acelera a transferência de massa e reduz a taxa de secagem de frutas e vegetais através do aumento da permeabilidade das membranas celulares. Assim, os processos combinados tendem a ser mais eficientes e econômicos do que a DO convencional, pois reduzem o tempo de operação e, consequentemente, o consumo de energia. Adicionalmente, os produtos desidratados gerados através de processos associados geralmente apresentam melhores características nutricionais e físico-químicas. Esta revisão sumariza os princípios básicos e aplicações da DO em combinação com outros métodos, com ênfase especial dada à produção de frutas secas.

Agro-Industrial Fruit Byproducts as Health-Promoting Ingredients Used to Supplement Baked Food Products.

One of the biggest problems faced by food industries is the generation of large amounts of agro-industrial byproducts, such as those derived from fruit processing, as well as the negative effects of their inadequate management. Approximately 1/3 of the food produced worldwide is unused or is otherwise wasted along the chain, which represents a burden on the environment and an inefficiency of the system. Thus, there is growing interest in reintroducing agro-industrial byproducts (both from fruits and other sources) into the processing chain, either by adding them as such or utilizing them as sources of health-promoting bioactive compounds. The present work discusses recent scientific studies on the nutritional and bioactive composition of some agro-industrial byproducts derived from fruit processing, their applications as ingredients to supplement baked foods, and their main biological activities on the consumer's health. Research shows that agro-industrial fruit byproducts can be incorporated into various baked foods, increasing their fiber content, bioactive profile, and antioxidant capacity, in addition to other positive effects such as reducing their glycemic impact and inducing satiety, all while maintaining good sensory acceptance. Using agro-industrial fruit byproducts as food ingredients avoids discarding them; it can promote some bioactivities and maintain or even improve sensory acceptance. This contributes to incorporating edible material back into the processing chain as part of a circular bioeconomy, which can significantly benefit primary producers, processing industries (particularly smaller ones), and the final consumer.

Bioaccessibility and antioxidant activity of phenolic compounds in frozen pulps of Brazilian exotic fruits exposed to simulated gastrointestinal conditions.

This study characterized the phenolic profile in siriguela, umbu-cajá and mangaba, as well in their frozen pulps (FPs). The bioaccessibility of phenolic compounds and the antioxidant activity of the FP dialysates were determined following exposure to simulated gastrointestinal conditions. The profile of phenolic compounds identified in fruit and FPs were relatively similar. After pulp processing, increases of 33.60% and 68.72% in free phenolics were observed for mangaba and umbu-cajá, respectively, whereas in siriguela, the free phenolic was reduced by 56.55%. Generally, phenolic levels decreased after exposure to simulated gastric conditions in all FPs. The bioaccessibility of phenolics varied among the evaluated FPs. The highest bioaccessibility was observed for gallic acid in the umbu-cajá FP (73.92%) and the lowest for gentisic acid in the mangaba FP (8.71%). Siriguela and umbu-cajá FP dialysates presented the highest capacity for the capture of the radical 2,2'-diphenyl-2-picrylhydrazyl hydrate, whereas the mangaba FP dialysate demonstrated the highest iron reducing capacity.

Effect of different ingredients contents on physical, physicochemical and sensory properties of the creamy banana marmalade cv. ‘nanica’(Musa cavendishii)

Banana is a highly perishable fruit, with a shelf life of 7 to 10 days, and the fruits being in excess or those in non conformity to be consumed are used to produce marmalade; and it is an interesting economic alternative. This study evaluated the effect of different ingredients on the physical, physicochemical and sensory properties of creamy banana marmalade. An incomplete factorial design (24-1) with two levels of four factors (pulp/sugarratio, pectin concentration, added amount of acid and sorbate concentration). The sensorial acceptance of marmalades was evaluated using a 9-point hedonic scale, and the purchase intention by employing a 5-pointscale. The analyzed variables mostly affecting the parameters were the pulp/sugar ratio, the added amount of acid and the sorbate concentration, due to their reaction with the marmalade components. The formulation 2 was preferred by consumers because of the firmest texture and the intensified yellow color.

Effect of different ingredients contents on physical, physicochemical and sensory properties of the creamy banana marmalade cv. ‘nanica(Musa cavendishii)

Banana is a highly perishable fruit, with a shelf life of 7 to 10 days, and the fruits being in excess or those in non conformity to be consumed are used to produce marmalade; and it is an interesting economic alternative. This study evaluated the effect of different ingredients on the physical, physicochemical and sensory properties of creamy banana marmalade. An incomplete factorial design (24-1) with two levels of four factors (pulp/sugarratio, pectin concentration, added amount of acid and sorbate concentration). The sensorial acceptance of marmalades was evaluated using a 9-point hedonic scale, and the purchase intention by employing a 5-pointscale. The analyzed variables mostly affecting the parameters were the pulp/sugar ratio, the added amount of acid and the sorbate concentration, due to their reaction with the marmalade components. The formulation 2 was preferred by consumers because of the firmest texture and the intensified yellow color.(AU)