Maria Aparecida Mauro

Acerola is a nutrient‐rich but highly perishable fruit that requires processing to preserve its nutritional quality. Foam mat drying is an effective method for retaining nutrients in liquid and semisolid foods, provided that suitable foaming agents are selected. The use of plant‐based foaming agents represents a promising solution to meet the demands of vegan and vegetarian consumers. Therefore, this study proposed to evaluate the influence of different plant‐based foaming agents and drying temperatures on the quality of acerola pulp powder. Acerola pulp was dried at 60°C and 70°C using soy protein isolate (SPI), concentrate of pea protein (CPP), distilled monoglycerides (Dimodan), and lactic acid esters (Lactem), and the effects on drying kinetics, nutrient retention, and color were investigated. Process parameters affected drying rates and were associated with the powder's nutritional characteristics. The diffusion model did not provide a satisfactory fit to represent the drying kinetics, suggesting anomalous diffusivity. The Page model demonstrated a precise fit and was associated with anomalous diffusion, with its exponent unequivocally indicating super‐diffusive behavior. Drying at 70°C favored vitamin C retention due to faster moisture removal, whereas 60°C better preserved phenolic compounds and carotenoids. SPI, in combination with fatty acid ester‐based agents, further enhanced vitamin C retention. Notably, all powders exhibited exceptionally high vitamin C content, exceeding 10 g per 100 g. These results underscore the potential of plant‐based foaming agents for producing nutritionally rich acerola powder through foam mat drying, a simple and readily applicable process for developing plant‐based food products. Practical Applications: This study addresses a simple, cost‐effective, and scalable process suitable for both small‐ and large‐scale production of acerola powder, an appealing ingredient for fortifying foods and beverages. The proposed process preserves nutritional compounds and demonstrates the viability of using plant‐based proteins as natural foaming agents, either alone or in combination with plant‐based fatty acid‐derived emulsifiers.

Devido à alta perecibilidade da acerola, procedimentos que visem à sua conservação e à preservação de seus nutrientes contribuem para o melhor aproveitamento dessa fruta, como a técnica conhecida como secagem em leito de espuma, que é simples e adequada a produtos líquidos e pastosos. O método consiste na mistura da polpa a agentes formadores de espuma e, em seguida, na desidratação da espuma em bandejas dispostas em secadores convencionais, o que possibilita desidratar a polpa em tempos relativamente curtos de secagem. Visando ao crescimento do público vegano, para o qual a aplicação de adjuvantes de origem vegetal é essencial, o presente trabalho tem o objetivo de avaliar os efeitos da formulação da espuma sobre o processo de secagem em leito de espuma de polpa de acerola, utilizando aditivos de origem vegetal, como isolado de proteína de soja (SPI), monoglicerídeos destilados e ésteres de mono e diglicerídeos de ácidos graxos com ácido láctico, ambos derivados de óleos vegetais e utilizados em quantidades permitidas pela legislação vigente. Os coeficientes de difusividade ficaram entre 1,33x10-9 m2/s a 2,79x10-9 m2/s em um tempo de 105 a 135 minutos e, em alguns tratamentos, houve a formação de grumos no pó. Dentre os aditivos testados, o melhor aditivo foi o SPI, que, ao ser aplicado na concentração de 1% sobre a polpa de acerola, proporcionou um pó solto e com características favoráveis

This study investigated the influence of blanching on the drying kinetics of papaya from the perspective of the microstructure of the tissue and the water sorption behavior. Drying kinetics and water effective diffusion coefficients were determined based on Fick’s law considering shrinkage. Intense cellular changes were observed in blanched tissues images obtained by light microscopy and transmission electron microscopy. Heat pretreatment increased the water diffusion coefficients and the drying rates in comparison with fresh fruit. Severe color changes were induced by blanching, resulting in color loss during drying. At intermediate moisture ranges, sorption isotherms of blanched papayas showed lower water sorption capacity than those of fresh fruit, therefore the critical moisture for microbial growth in fresh papayas is higher than in blanched ones. The compensation theory was satisfied for fresh fruit but not for blanched fruit, which presented distinctive sorption behavior attributed to cellular damage caused by heat pretreatment.

Edible coatings based on polysaccharides have been applied on pieces of fruits and vegetables before drying because of their potential to improve physical and nutritional characteristics of dehydrated plant foods. In the present study, physical and thermal properties of pectin-based films, with and without the incorporation of by-products obtained from the processing of red guava, were determined. These properties allow one to predict the likely behaviour of these films when used as edible coatings on guava pieces, during and after their dehydration. Thus the structural and morphological characteristics and the physical, thermal and sorption properties of the films and of the fruit pulp were determined, using scanning electronic microscopy (SEM), differential scanning calorimetry (DSC), X-ray diffraction (XRD) and the static gravimetric method to determine the water-sorption curves. The addition of by-products provided crystallinity to the pectin film, attributed to their cellulose content, and hardly altered the water retention capacity of the pectin films. However, the pectin contributed to presenting a slightly higher sorption moisture at equilibrium, as compared to the guava pulp. The glass transition temperatures reported at extremely low moisture contents, both in the pulp and in the films with added by-products, indicated that at intermediate moisture contents, the fruit/film ensemble was in the rubbery state at room temperatures, providing softness to the dehydrated product. The images showed good integration of the edible films with the surface of the guava pieces.