Rita de Cássia dos Santos Navarro da Silva

Otimização da aceitabilidade sensorial de requeijão cremoso light

Cream cheesecurd is a type of processed cheese, originally Brazilian, produced throughout the entire Brazilian territory with some technological variations. This is one of the main types of cheese produced and consumed in Brazil and it is known for presenting an elevated fat content. On the other hand, the fat plays a fundamental role in appearance, flavor and texture of cheese, then developing a light product with sensory quality similar to the traditional version is a major challenge to food industry. In this context, the objective of this study was to evaluate the chemical composition and sensory acceptability of light cream cheesecurd with different levels of fat reduction for texture and overall impression. The experiment followed a design of response surface, the Central Composite Rotatable Design (CCRD) with two factors (fat and moisture). The sensory acceptability was evaluated by 100 consumers, by the hedonic scale of nine points. The results showed that the cheesecurds with different levels of fat reduction had similar sensory acceptability when combined with a proportional increase in moisture content. The products that presented dry defatted extract (DDE) of approximately 19.3%, originated from different combinations of fat and moisture, were those with better acceptance by consumers, demonstrating the importance of DDE in sensory acceptance.

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.

Análise conjunta de fatores baseada em escolhas no estudo da embalagem de iogurte light sabor morango

A análise conjunta de fatores baseada em escolhas (ANCFE) foi empregada para avaliar a influência de alguns fatores da embalagem de iogurte light sabor morango sobre a escolha do consumidor. Foram selecionados três fatores com dois níveis cada para a montagem das embalagens: conteúdo de açúcar (“0% de açúcar” e “com adoçante”), conteúdo de gordura (“0% de gordura” e “baixo teor de gordura”) e conteúdo de proteína (“enriquecido com proteínas bioativas” e “enriquecido com proteínas do soro do leite”). Oito imagens de embalagens foram criadas baseando-se em um arranjo fatorial completo. Estas imagens foram apresentadas a 144 consumidores, aos quais foi solicitado que escolhessem apenas uma dentre elas. Pela ANCFE, o produto ideal ou de maior probabilidade de escolha para os consumidores seria a embalagem de iogurte contendo as informações “0% de açúcar”, “0% de gordura” e “enriquecido com proteínas bioativas”. A ANCFE demonstrou ser eficiente em testes que envolvem a influência de características não sensoriais do produto sobre a avaliação do consumidor, permitindo, de maneira objetiva, interpretar dados em situações que envolvem a relação entre a análise sensorial e o estudo do comportamento do consumidor.

A spreadsheet for calculation of ingredients for standardization of requeijão cremoso

The standardization of requeijao cheese quality characteristics is a processing stage which is directly influenced by the chemical composition of the raw material. Fat and water concentrations are the main factors that cause variation in quality properties of the requeijao and, when not thoroughly controlled, may cause a lack in standardization of the food. Calculations of ingredients for effective standardization must be made in relation to the final product through of iterative calculations, which makes the manual process unfeasible. Thus, the objective of the present study was to develop a spreadsheet for ingredient calculation, with restrictions being the different concentrations of fat and water in order to standardize the final products. The spreadsheet was developed using the Excel 2007® Solver function, with just four input data: quantity of mass, water and fat content of the mass and fat content of the cream. The optimal solution was that which maximizes the amount of final product while meeting the stipulated constraints of fat and water. Results obtained with the spreadsheet were validated by processing the requeijao cheeses and comparison of the theoretical and practical parameters using the t-test. There was no significant difference between fat and water contents (p>0.10) estimated and verified in practice. Therefore, the use of the spreadsheet proved to be efficient for standardization of requeijao formulations.

ANÁLISE DE RISCO NA AVALIAÇÃO DA INFLUÊNCIA DA MARCA NA ACEITABILIDADE NÃO SENSORIAL DE REQUEIJÃO CREMOSO

Consumer behavior is influenced by intrinsic (sensory characteristics) and extrinsic (non-sensory characteristics) of the product. Among the non-sensory factors, highlights been studied by various areas of knowledge and strength channeled through companies in order to entice the consumer at the time of purchase. In recent decades, many statistical methods have been employed in order to study this important influence on consumer behavior, both in marketing as in sensory analysis. This study aimed to evaluate the impact of brand on the acceptance of cheese using the statistical technique of relative risk. Thus, the sensory test was conducted in two sessions, with the first, the samples were presented coded (test without information) and the second presented with their respective brands. Comparing the results obtained for the two sessions, it was found that there was no change in acceptance of the cheesecurd for all brands and technical statistical analysis showed the relative risk of easy application, interpretation and effective in studies of non-sensory characteristics of food.

ACEITAÇÃO SENSORIAL DE IOGURTE SABOR PÊSSEGO ACRESCIDO DE DIFERENTES CONCENTRAÇÕES DE AROMA E POLPA POR MEIO DA TÉCNICA DE MAPA DE PREFERÊNCIA

The objective of the present study was to evaluate the effect of different pulp and artificial flavor concentrations on the physicochemical and sensory quality of peach-flavored yogurt, applying the statistical technique of the Principal Component Analysis (PCA) for developing an Internal Preference Map. Therefore, an acceptance test was performed with 150 consumers using the nine-point hedonic scale. Physicochemical determinations of titratable acidity, lipids, lactose and sucrose were also conducted. There was a significant difference (p < 0.05) between the yogurt formulations in relation to sensory acceptability, while in the case of the physicochemical measurements the formulations showed no difference at the level of 0.05 probability by the F-test. It was found that the addition of artificial flavor during yoghurt processing may be suspended at the Lindo Vale Dairy without altering sensory acceptability of the product, thus reducing production costs while maintaining the sensory quality of the product. However, the pulp concentration in peach-flavor yogurt cannot be reduced without altering sensory acceptability, so that the pulp concentration in the dairy product is maintained.