Suzana Maria Della Lucia

Methodology for determination of two new sensory thresholds: Compromised acceptance threshold and rejection threshold

The existing methodologies for determining thresholds generate unreliable estimates of the point at which the intensity of a stimulus begins to compromise acceptance or result in sensory rejection of a product. Thus, a new methodology was proposed for determination of two new sensory thresholds: the compromised acceptance threshold (CAT) and the rejection threshold (RT). In this new methodology, increasing or decreasing series of stimulus intensity are measured together with a standard stimulus (control sample) by means of acceptance tests. In the present study, the CAT and RT were determined for sucrose concentrations in grape nectar, demonstrating that when reducing the sucrose concentration of grape nectar form 9.00% (w/v) to 6.87% there begins to occur impairment of product acceptance (CAT), and when reducing the sucrose concentration from 9.00% to 3.83% there begins to occur sensory rejection (RT) of the product. When compared to existing threshold determination methodologies, the proposed methodology permitted for calculating, with greater reliability, the points at which compromise of acceptance (CAT) and sensory rejection (RT) of the product begin to occur. In addition to the case study presented, the proposed methodology has a wide range of applications in science and in the food, cosmetic and pharmaceutical industries.

Artificial neural networks (ANN): prediction of sensory measurements from instrumental data

The objective of this study was to predict by means of Artificial Neural Network (ANN), multilayer perceptrons, the texture attributes of light cheesecurds perceived by trained judges based on instrumental texture measurements. Inputs to the network were the instrumental texture measurements of light cheesecurd (imitative and fundamental parameters). Output variables were the sensory attributes consistency and spreadability. Nine light cheesecurd formulations composed of different combinations of fat and water were evaluated. The measurements obtained by the instrumental and sensory analyses of these formulations constituted the data set used for training and validation of the network. Network training was performed using a back-propagation algorithm. The network architecture selected was composed of 8-3-9-2 neurons in its layers, which quickly and accurately predicted the sensory texture attributes studied, showing a high correlation between the predicted and experimental values for the validation data set and excellent generalization ability, with a validation RMSE of 0.0506.

Características visuais da embalagem de café no processo de decisão de compra pelo consumidor

Conduziu-se este trabalho, com o objetivo de investigar, usando grupos de foco, atitudes, opinioes, conceitos e pensamentos de consumidores sobre embalagens de cafe torrado e moido que refletem na sua decisao de compra. Tres sessoes de grupo de foco de 90 minutos foram realizadas (duas em Vicosa/MG e uma em Londrina/PR), num total de 24 participantes. Foram apresentadas cinco embalagens de cafe (sendo quatro orgânicas, em razao da maior preocupacao em obter dados sobre cafe orgânico) para estimular a conversacao, sendo seguido um roteiro de perguntas. Os dados obtidos foram estudados, considerando palavras utilizadas pelos consumidores, sem analise estatistica, em razao da caracteristica qualitativa de grupos de foco. Foi observado que os principais fatores considerados no processo de decisao de compra sao: preco, cor da embalagem e marca. Muitos participantes mostraram-se fieis a marcas e outros admitiram pagar mais por um produto orgânico, dependendo do preco do mesmo. Foi sugerido que na embalagem de cafe orgânico deveria ser salientada a definicao do produto para aqueles que nao conhecem tal tecnica de producao.

Ordered probit regression analysis of the effect of brand name on beer acceptance by consumers

Ordered probit regression was used to analyze data of sensory acceptance tests designed to study the effect of brand name on the acceptability of beer samples. Eight different brands of Pilsen beer were evaluated by 101 consumers in two sessions of acceptance tests: blind evaluation and brand information test. Ordered probit regression, although a relatively sophisticated technique compared to others used to analyze sensory data, was chosen to enable the observation of consumers’ behavior using graphical interpretations of estimated probabilities plotted against hedonic scales. It can be concluded that brands B, C, and D had a positive effect on the sensory acceptance of the product, whereas brands A, F, G, and H had a negative influence on consumers’ evaluation of the samples. On the other hand, brand E had little influence on consumers’ assessment.

Bebida com adição de soro de leite e fibra alimentar prebiótica

O objetivo deste trabalho foi avaliar a aceitacao sensorial de bebida nao fermentada, com adicao de inulina e polpa de acerola. Seis formulacoes foram desenvolvidas, com adicao de 0, 20, 40, 60, 80 e 100% de soro. O pH do soro foi 6,59, e a acidez de 0,103% de acido latico. Utilizou-se a escala hedonica de nove pontos no teste de aceitacao. As medias hedonicas das amostras com 0, 20 e 40% de soro nao diferiram significativamente e variaram entre 6 e 8 pontos. As bebidas desenvolvidas com ate 60% de soro sao alternativas interessantes para o aproveitamento desse subproduto em laticinios.

ÓLEOS ESSENCIAIS DE MANJERICÃO E GENGIBRE NA AROMATIZAÇÃO DE AZEITE DE OLIVA

O presente trabalho teve como objetivo aromatizar azeite de oliva com oleos essenciais de manjericao e gengibre e determinar a composicao quimica dos compostos presentes nos respectivos oleos. Os oleos essenciais de manjericao e gengibre foram obtidos por hidrodestilacao e analisados por cromatografia gasosa (CG) e por cromatografia gasosa acoplada a espectrometria de massas (CG-EM). Os azeites de oliva aromatizados foram submetidos a analise sensorial. Os componentes majoritarios determinados para o oleo essencial de manjericao foram o 1,8-cineol (33,63%) e linalol (35,29%). Os seis principais componentes volateis encontrados no oleo essencial de gengibre foram o citral, a mistura de geranial (18,79%) e neral (9,90%), -Amorfeno (10,38%), canfeno (9,98%), -felandreno (9,32%) e E,E-- farneseno (8,83%). Os resultados da analise sensorial revelaram boa aceitacao para os dois azeites formulados, indicando a existencia de um mercado a ser explorado.

Características físico-químicas de bebidas de café tipo expresso preparadas a partir de blends de café arábica e conilon

In recent years, there has been a growing interest for exquisite beverages such as espresso coffee. Espresso coffee requires a high content of the aqueous extract to ensure a good body of the beverage, which can be obtained using coffee conilon. Espirito Santo State is the largest producer of conilon coffee in Brazil. Although there are several studies on the physico-chemical composition of Brazilian coffee, there is a lack of information about the use of conilon from Espirito Santo in the formulation of blends with Arabica coffee, as well as the physico-chemical characteristics of espresso coffee beverage obtained with these blends. The objective of this study was to carry out the physico-chemical characterization of espresso coffee beverage made ​​from blends of arabica and conilon coffees (in arabica and conilon proportions of 100:0; 80:20; 60:40; 40:20 and 0:100, respectively) with different types of processing (dry process and semi dry process) produced in Espirito Santo. The variables moisture, pH, titratable acidity and aqueous extract of the samples were analyzed. It was found that the use of conilon in blends with Arabica, in the two forms of processing, results in beverages with higher levels of pH, lower acidity and higher percentage of aqueous extract. A higher percentage of aqueous extract is interesting for the preparation of espresso coffee. The results demonstrate the feasibility of using conilon coffee in blends with Arabica coffee in brewing espresso coffee, when a higher aqueous extract beverage is desired.