76 research outputs found
Sucrose in the concentrated solution or the supercooled “state” : a review of caramelisation reactions and physical behaviour
Sucrose is probably one of the most studied molecules by food scientists, since it plays an important role as an ingredient or preserving agent in many formulations and technological processes. When sucrose is present in a product with a concentration near or greater than the saturation point—i.e. in the supercooled state—it possesses high potentialities for the food industry in areas as different as pastry industry, dairy and frozen desserts or films and coatings production. This paper presents a review on critical issues and research on highly concentrated sucrose solutions—mainly, on sucrose thermal degradation and relaxation behaviour in such solutions. The reviewed works allow identifying several issues with great potential for contributing to significant advances in Food Science and Technology.Authors are grateful for the valuable discussions with Teresa S. Brandao and Rosiane Lopes da Cunha during this research. Author M. A. C. Quintas acknowledges the financial support of her research by FCT grant SFRH/BPD/41715/2007
Centesimal composition and physical-chemistry analysis of the edible mushroom Lentinus strigosus occurring in the Brazilian Amazon
The centesimal composition and the physical and chemical analyses of Lentinus strigosus, an edible mushroom occurring in the Brazilian Amazon and produced in alternative substrates based on wood and agroindustrial residues, were evaluated. For this purpose, the C, N, pH, soluble solids, water activity, protein, lipids, total fiber, ash, carbohydrate, and energy levels were determined. The substrates were formulated from Simarouba amara Aubl. marupá"), Ochroma piramidale Cav. Ex. Lam. pau-de-balsa") and Anacardium giganteum cajuí") sawdust and Bactris gasipaes Kunth pupunheira") stipe and Saccharum officinarum (sugar cane bagasse). The results indicated that the nutritional composition of L. strigosus varied with the substrate of cultivation; the protein levels found in mushrooms grown in the different substrates (18 –21.5%) varied with the substrate and was considered high; the soluble solids present in the mushrooms could have a relation with complex B hydrosoluble vitamins. L. strigosus could be considered as important food owing to its nutritional characteristics such as high protein content, metabolizable carbohydrates and fibers, and low lipids and calories content.Avaliou-se a composição centesimal e análise físico-química do Lentinus strigosus, um cogumelo comestível de ocorrência na Amazônia brasileira, produzidos em substratos alternativos à base de resíduos madeireiros e agroindustriais. Com este objetivo, determinou-se C, N, pH, sólidos solúveis, atividade de água, proteína, lipídios, fibra total, cinzas, carboidratos e energia. Os substratos foram formulados a partir de serragem de Simarouba amara Aubl. (marupá), Ochroma piramidale Cav. ex. Lam. (pau-de-balsa) e Anacardium giganteum (cajuí); e do estipe de Bactris gasipaes Kunth (pupunheira) e de Saccharum officinarum (cana-de-açúcar). Os resultados demonstraram que: a composição nutricional do L. strigosus variou com o substrato de cultivo; os valores de proteína encontrados nos cogumelos cultivados nos diferentes substratos (18 - 21,5%) variaram de acordo com o substrato, sendo considerados elevados; os sólidos solúveis presentes nos cogumelos podem ter relação com vitaminas hidrossolúveis do complexo B; o L. strigosus pode ser considerado um importante alimento devido suas características nutricionais: alto teor de proteína, carboidratos metabolizáveis e fibras; baixos teores de lipídios e de calorias
Análise físico-química, microbiológica e sensorial de frutos de manga submetidos à desidratação osmótico-solar
Some thermal and physical changes in a glucose-glycine solution undergoing Maillard reaction
Evaluation of viscosities of amorphous phases in frozen systems by WLF kinetics and glass transition temperatures
The viscosities of concentrated solutions of glucose, fructose, sorbitol and xylitiol were measured by a falling sphere method. The measured viscosities
were compared with those predicted by WLF kinetics from glass transition temperatures.
Discrepancies between measured and predicted viscosities were found
to be within an order of magnitude of 0.3 on log E. Experimental data on
sucrose solutions obtained from literature sources were also compared with
WLF predicted values. The viscosities of the amorphous phases in frozen or
partially frozen sucrose-, glucose-, fructose-, citric acid-, dimethyl sulfoxide-,
polyvinylpyrrolidone- and glycerol-water systems were estimated by WLF
kinetics and freezing temperatures. At equal sub-freezing temperature, the
viscosities increased with the increasing of molecular weight. In addition,
viscosity changes during devitrification and recrystallization of 60-70% sucrose
solutions, which do not freeze upon cooling, were evaluated
Experimental and predicted viscosities of model solutions at temperatures above the glass transition
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