Validação do uso de fotografias para avaliação visual da carne de bovinos terminados em confinamento, com ou sem adição de óleos essenciais na dieta

• Autor(a) principal: Passetti, Rodrigo Augusto Cortêz
• Data de Publicação: 2016
• Tipo de documento: Dissertação
• Idioma: por
• Título da fonte: Repositório Institucional da Universidade Estadual de Maringá (RI-UEM)
• Texto Completo: http://repositorio.uem.br:8080/jspui/handle/1/1850
• topic: Carnes bovina; Animais em confinamento; Óleo essencial de cravo; Dieta de bovinos; Óleo essencial de canela; Cor; Imagens digitais; Brasil.; Colour; Clove; Cinnamon; Images; Brazil.; Ciências Agrárias; Zootecnia

Colour perception plays a major role in evaluation of meat quality, especially during purchasing. The traditional sensorial methodology of assessing meat color evolution in displays is complex, expensive and demands long duration. Photographs are an alternative to overcome these difficulties thus the validation of this methodology becomes necessary. Thus, the objective of this study was to compare perception of meat between viewing meat directly in displayer and their corresponding photographs to assess the reliability and accuracy of using food photographs as an assessment tool. Forty Schwyz vs. Nellore bulls (half-brothers), 12 month-old, average live weight (LW) of 219 + 11.7 kg were used in a complete randomized design and distributed in three diets groups: CON (n = 8) - diet without addition of essential oils; CLO (n = 16) - diet with 5,000 mg/animal/day of clove essential oils and CIN (n = 16) - diet with 5,000 mg/animal/day of cinnamon essential oils. After slaughter two-centimeters thick steaks were cut from longissimus thoracis and frozen. For the visual analyses steaks were thawed and packaged individually in trays with film and displayed at 4 ± 1°C under simulated retail conditions using fluorescent light (1200 lx, 12 h on) in a commercial expositor. Seventeen consumers (8 male and 9 female) evaluated visual acceptability of appearance. Consumers using a 9-point structured hedonic scale (one = dislike 30 extremely to nine = like extremely) to assess the visual acceptability of the meat. The shelf-life of meats was determined by the number of days which samples were assigned with scores higher than 5.0. Each consumer attended two evaluation sessions separated by a two week interval. In the first session consumers evaluated samples directly in a commercial expositor (Trays) and in the second session consumers evaluated correspondent photos of samples in sequential (Sequential) and randomized order (Random). Variance of the scores assigned and its respectively standard deviations were analyzed by GLM model (Tukey 5.0%). Effect of days of display was analyzed with a simple regression. All statistical analyses were performed by the IBM Statistical Package for the Social Science (SPSS). CON diet group resulted on higher scores 6, 7 and 8 of display and higher shelf-life than essential oils diets. Trays and Sequential photos scores were similar in the majority of days thus digital images could be used to evaluate color evolution. However random photos resulted in lower scores in the first days and lower decrease in scores than sequential and random photos (P<0.05) from the second to fifth day. When evaluated the standard deviations, Trays and Sequential presented equal or higher deviation than Random in the majority of days. Trays presented a higher fluctuation in the standard deviation through the display period, thus it was concluded that digital images promoted a higher standard situation for evaluations because differences between consumers remained constantly through the eleven days.