Caroline Sefrin Speroni

Polyphenol extraction optimisation from Ceylon gooseberry (Dovyalis hebecarpa) pulp

Originally from Asia, Dovyalis hebecarpa is a dark purple/red exotic berry now also produced in Brazil. However, no reports were found in the literature about phenolic extraction or characterisation of this berry. In this study we evaluate the extraction optimisation of anthocyanins and total phenolics in D. hebecarpa berries aiming at the development of a simple and mild analytical technique. Multivariate analysis was used to optimise the extraction variables (ethanol:water:acetone solvent proportions, times, and acid concentrations) at different levels. Acetone/water (20/80 v/v) gave the highest anthocyanin extraction yield, but pure water and different proportions of acetone/water or acetone/ethanol/water (with >50% of water) were also effective. Neither acid concentration nor time had a significant effect on extraction efficiency allowing to fix the recommended parameters at the lowest values tested (0.35% formic acid v/v, and 17.6 min). Under optimised conditions, extraction efficiencies were increased by 31.5% and 11% for anthocyanin and total phenolics, respectively as compared to traditional methods that use more solvent and time. Thus, the optimised methodology increased yields being less hazardous and time consuming than traditional methods. Finally, freeze-dried D. hebecarpa showed high content of target phytochemicals (319 mg/100g and 1,421 mg/100g of total anthocyanin and total phenolic content, respectively).

Obtenção e caracterização de farinha de casca de uva e sua utilização em snack extrusado

This study aimed to characterize grape skin flour (GSF) and the effect of its inclusion in an extruded snack, with regard to the nutritional, technological and sensory parameters. Grape pomace from the cultivar Marselan (Vitis vinifera), obtained during the winemaking process, was used to obtain the grape skin flour. The in natura pomace was dried in a forced air oven at 55 °C for 24 hours. The skins were separated from the seeds using 2 mm and 3 mm sieves, and the skins subsequently ground in a micro mill at 27.000 rpm (particles < 1 mm) and stored at –18 °C. The grape skin flour obtained was submitted to a chemical analysis (moisture, ash, protein, lipids, total dietary fibre, carbohydrates, pH, phenolic compounds and colour). The GSF was included in the formulation of an extruded snack at levels of 9% and 18%, substituting the corn flour, representing 5% and 10% fibre, respectively. The snacks were evaluated for colour, texture and acceptance. A microbiological analysis for coliforms at 45 °C and Salmonella was carried out on the test formulations. Fibre (58.01%), ash (12.46%) and carbohydrates (17.62%) were the main constituents of the grape skin flour, which had a pH value of 3.51. The phenolic compounds resveratrol (6.14 mg.g–1), luteolin (5.16 mg.g–1) and kaempferol (3.01 mg.g–1) were detected in the largest amounts in the GSF, indicating the presence of antioxidants in the flour. The snack containing 9% (5% fibre) of GSF showed the best results for acceptance with respect to the attributes of colour, aroma and texture as compared to the standard snack. The addition of GSF to extruded snacks is feasible and of interest due to its nutritional enrichment (fibre and phytochemicals) and aggregation of value to a byproduct discarded by wineries.

Grape Pomace Skins and the Effects of Its Inclusion in the Technological Properties of Muffins

ABSTRACT The present study evaluated the incorporation of 5, 7.5, and 10% of Riesling skin flour (RSF) and Tannat skin flour (TSF) as wheat flour replacement in muffins. The flour was evaluated for gluten content and Alveograph parameters. The finished products were evaluated for chemical composition and technological properties, and a sensory analysis was performed. All samples presented higher dietary fiber content than wheat flour, and this was mainly in the form of soluble dietary fiber. The inclusion of grape skin flour decreased the lightness of the flour and increased the lightness values (L*) of the muffin crumbs and crusts. The hardness of the muffins that incorporated RSF and TSF muffins increased as the percentage of the skin flour increased. There was a decrease in the cohesiveness value as the skin flour percentage increased. Consumers did not perceive the levels of substitution. The results of the sensory analysis indicated that grape skin can be added to the ingredients of muffins without changing the color, taste, flavor, texture, and overall acceptability of the final product.

Alternative protein sources in nutrition and metabolism of jundiá: "in nature" and demucilaged linseed meal

Este estudo avaliou o crescimento e efeitos metabolicos da substituicao parcial da fonte proteica de origem animal pelos farelos de linhaca in natura (FL) e demucilada (FLD) na dieta de juvenis de jundia (Rhamdia quelen). Apos a demucilagem, os niveis de proteina bruta aumentaram e houve reducao da fibra soluvel do farelo de linhaca. Durante sete semanas, 240 juvenis de jundia foram criados em sistema de recirculacao de agua e alimentados ate a saciedade aparente com as seguintes dietas: dieta controle (farinha de carne e ossos e concentrado proteico de soja como as principais fontes proteicas); 17%FL (17% da proteina bruta do farelo de linhaca em substituicao da farinha de carne e ossos); 17% FLD (17% da proteina bruta do farelo de linhaca demucilada em substituicao da farinha de carne e ossos); 35%FLD (35% da proteina bruta do farelo de linhaca demucilada em substituicao da farinha de carne e ossos). Ao final do experimento, peso e comprimento total e padrao nao diferiram entre os tratamentos, porem menores valores de conversao alimentar foram encontrados no grupo controle. Em relacao as repostas metabolicas, os animais alimentados com 35%FLD apresentaram maiores niveis de glicose e colesterol no plasma, porem triglicerideos, albumina, proteinas totais e os parâmetros bioquimicos do figado (glicogenio, glicose, lactato, proteina, aminoacidos, amonia) nao foram alterados entre os tratamentos. Os resultados demonstraram que tanto o farelo de linhaca in natura como o demucilado podem ser utilizados na dieta de jundias sem comprometer os parâmetros metabolicos e de peso final.

Crambe (Crambe abyssinica) and sunflower (Helianthus annuus) protein concentrates: production methods and nutritional properties for use in fish feed

The purpose of this study was to develop and improve protein concentration techniques for two industrial by-products with the potential for use in fish feed. In particular, we chemically characterized crambe meal and sunflower meal and their protein concentrates. Three different protein concentration methods were tested: isoelectric pH (pHi), acid pH and alkaline pH. For crambe and sunflower meals extraction using the pHi method was most efficient in terms of protein yield and crude protein content in the concentrates; this method also increased lysine and methionine content in the concentrates. The water holding capacity of the sunflower protein concentrate was greater than that of the crambe protein concentrate. The crambe protein concentrate had a foam-formation capacity of 15%, which stabilized at 6% after 90 minutes. The protein concentration method also reduced total phenolic content by approximately 50% in the concentrates compared with the meals. Therefore, we conclude that protein concentration using the pHi method is the most efficient technique for crambe and sunflower meals, and the use of this technique can decrease total phenolic compounds while improving meal quality for fish feeding.