Propriedades físicas de misturas para sherbet de mangaba

Abstract

Resumo -O objetivo deste trabalho foi avaliar a viscosidade, a quantidade de água não congelada (w nc ) e a temperatura de transição vítrea da fração maximamente crioconcentrada (Tg') de misturas para sherbet, e a incorporação de ar (IAr) dos sherbets, com diferentes concentrações de goma guar (0,2% a 0,5%) e polpa de mangaba (21,1%, 25,8% e 28,6% o C e não apresentou diferença entre as amostras. A IAr foi de 20,01% a 40,59%. Sherbets com a mesma concentração de polpa apresentaram valores diferentes desta variável, mas uma relação entre o aumento da quantidade de goma guar e maior IAr foi observada somente para os sherbets com 25,8% de polpa. O estabilizante interfere na viscosidade da mistura e IAr, e a concentração de polpa influencia as propriedades térmicas. O aumento de IAr proporciona melhor maciez ao produto. Maior quantidade de polpa diminui a w nc , assim o produto terá menos água disponível para migrar e formar cristais de gelo maiores durante as oscilações na temperatura, diminuindo a qualidade do produto.Termos para indexação: sorvete, viscosidade, incorporação de ar, água não congelada, calorimetria diferencial de varredura. Physical properties of mixes to mangaba sherbetAbstract -Viscosity, unfrozen water (w nc ) and glass transition temperature of the maximally freeze-concentrated material (Tg') of sherbet mixtures and the overrum of the sherbets with different concentrations of guar gum (from 0.2% to 0.5%) and mangaba pulp (21.1%, 25.8% and 28.5%) were evaluated. Apparent viscosity ranged from 85.8 to 286.1 cP, increasing with guar gum concentration and mangaba pulp. Thermal analysis using differential scanning calorimetry of sherbets mixture showed that w nc was from 12% to 20%, decreasing with the increasing of mangaba pulp concentration. The Tg' ranged from -57.65 o C to -53.45 o C and was not different between the samples. The overrum was from 20.1% to 40.59%. Sherbets containing the same pulp concentration presented different values of this variable, however a relationship between the increasing of guar gum concentrations and the air incorporation was observed only for sherbets with 25.8% of mangaba pulp. The stabilizer modified the viscosity of the mixture and overrum and the pulp concentration influenced thermal properties. Higher overrum is better for product smoothness. Higher pulp concentration decreases the w nc so, the product concentrates less water available to form great ices during the changes in the temperature which may cause losses in the product quality.

Ice creams made from cow’s and goat’s milks with different fat concentrations: physical-chemical and sensory properties

“…The glass transition is less visible than the endothermic peak because of the greater energy variation involved in the second phenomenon (Sobral et al, 2001); it can be better visualised in an amplified scale (supplementary material). This behaviour is common in high water systems such as those typical of ice cream mixes (Goff et al, 1993;Oliveira et al, 2005). Indeed, the ice creams produced in this study presented humidity between 61 and 67% (wb) (Table 2).…”

“…The amount of unfrozen water (w uf ) in the samples was calculated from Equation 1 (Oliveira et al, 2005):…”

Functionality of kumquat (Fortunella margarita) in the production of fruity ice cream

“…The higher viscosity of the control sample may be due to the smaller air cells present in it . Oliveira et al reported that higher mangaba pulp concentrations increased the apparent viscosity and soluble solid content and also contributed to reducing free water in the mixture, a desirable characteristic in frozen desserts such as ice creams. In the present study, when we increased the KP concentration to 5, 10 and 15% (samples B, C and D respectively), the apparent viscosity decreased owing to the low total solid content of the mixes compared with the control sample.…”

Mangaba (Hancornia speciosa Gomez) ice cream prepared with fat replacers and sugar substitutes

“…Mangaba (Hancornia speciosa Gomez) is a typical Cerrado biome fruit widely used in regional gastronomy and has recently attracted increasing interest due to its considerable potentialities which have stimulated its sustainable cultivation in the Brazilian Northeast and West Central Regions (SOUSA et al, 2005). Oliveira et al (2005) used mangaba to prepare sherbet (a product made with water, sugar, fruit, milk solids, stabilizers, and colorings) and observed that higher pulp concentrations increased the apparent viscosity and soluble solids contents, and it also contributed to reduce free water in the mixture, a desirable characteristic in frozen desserts such as ice creams.…”