Correlation between sensory and instrumental texture analysis of expanded and flake-shaped breakfast cereals

Author(s)

Liara Silva Dias Faceto

• Document type: Doctoral Thesis
• Press: São José do Rio Preto. 2019-05-21.
• Institution: Universidade Estadual Paulista (Unesp). Instituto de Biociências Letras e Ciências Exatas. São José do Rio Preto
• Defense date: 2019-04-26
• Advisor: Ana Carolina Conti Silva

Abstract

The texture involves several sensory characteristics and is considered a critical attribute for the quality of some products, such as breakfast cereals. Breakfast cereals can be obtained through two main technological processes: thermoplastic extrusion and lamination, and both result in crispy products with reduced water activity. Few studies are found in the scientific literature regarding the instrumental and sensory texture characterization of expanded and flake-shaped breakfast cereals, as well as studies that correlate these analyzes. Thus, the general aim of this study was to determine the sensory texture profile of commercial expanded and flake-shaped breakfast cereals, dry and after milk addition, and the correlation between sensory and texture analysis of these foods. Expanded breakfast cereals crowdedshaped (AB), ball-shaped (B1, B2, B3 and B4) and donut-shaped (R), and the flake-shaped (F1 to F8) were used. The cereals were evaluated dry and after milk addition. Instrumental tests of force and acoustic properties were performed using a texture analyzer with a coupled acoustic detector, and force and acoustic properties were obtained through different tests /probes. The sensory characteristics of texture were evaluated through descriptive analysis and acceptance using hedonic scale. The expanded cereals were also characterized through scanning electron microscopy. The force and acoustic properties measured through the different types of force/probes application were discriminated among the expanded cereals and the flake-shaped cereals. The sensory texture profile of the expanded cereals was described through fracturability, hardness, crispness, chewiness and adhesiveness, while the flake-shaped cereals was described by hardness, crispness and adhesiveness. The milk addition resulted in expanded cereals fracturability loss and in the change of the flake-shaped cereal F1 texture profile. The high intensity of hardness impaired the acceptance of this attribute in dry expanded cereals, but improved their acceptance after milk addition, while increasing the adhesiveness of the flake-shaped cereals after milk addition impaired the adhesiveness acceptance of these products. Microscopically, only B3, B4 and R expanded cereals have undergone significant alteration of their internal structure by milk addition. For dry expanded breakfast cereals, the blade set (guillotine and "V" shaped) and Ottawa (with both plates) stood out in the instrumental and sensory correlations, whereas only the probe blade set with guillotine stood out after the milk addition. For flake-shaped cereals, there was greater diversity among the probes to correlate with the sensory characteristics, being blade set with guillotine, Ottawa (both plates) and Kramer highlighted for dry cereals, and the probes blade set with guillotine and Ottawa 17 blades for the cereals after adding milk. The acoustic analysis conditions used allowed strong correlations between instrumental and sensory acoustic characteristics. The good correlations between sensory and instrumental analysis found in this study show that instrumental evaluation methods for breakfast cereals texture, whether expanded or flakeshaped, dry or after milk addition, are representative of sensory methods and can be used by the food industry, saving time and reducing costs. (AU)