Dados do Trabalho

Título

NUTRITIONAL AND PHYSICAL-CHEMICAL CHARACTERIZATION OF FRESH AND FREEZE-DRIED PORCINE KIDNEY

Introdução

By-products from the meat industry have gained emphasis in recent years due to the need to fully utilize carcasses, caused by increased consumption across the globe. The kidney is equivalent to approximately 2.50% of the porcine carcass and has potential application, as it is permitted as an ingredient in food for non-ruminant animals and humans, provided that hygienic-sanitary inspection is rigorous. In this context, this work characterized fresh and freeze-dried porcine kidney in terms of physical-chemical and microbiological characteristics.

Material e Métodos

Porcine kidney samples were obtained from a slaughterhouse with a federal inspection service, shortly after slaughter. The samples were stored in thermal boxes and sent to the laboratory, where characterization and microbiological analyses were carried out on the fresh kidney. The samples were freeze-dried (48h, ~0.14 mmHg, -50 ºC) and evaluated for moisture, water activity (Aw), color, hygroscopicity, density and particle size.

Resultados e Discussão

Fresh kidney presented approximately 74.25% moisture, 15.76% protein, 5.39% ash, 4.16% carbohydrates and 0.44% lipids. The color parameters obtained were L*= 20.59, a*= 8.07, b*= 4.68, pH 6.41 and Aw 0.97 at 23.23 ºC. A value of 3.98 log CFU.g-1 was observed in the count of mesophilic microorganisms, which is within the microbiological standards required by current legislation. The freeze-dried viscera showed a reduction in moisture (4.25%) and Aw (0.40; at 24.80 ºC) and color changes (L*= 31.45; a*= 6.26 and b*= 10.88), generating a lighter product, with a decrease in red color and an increase in yellow. The hygroscopicity was 16.06%. The bulk density corresponded to 220.37 kg/m3, while in granulometry the lyophilized kidney appeared as a granular solid, with a Sauter diameter of 0.511.

Conclusão

The calculated ΔE (12.63) proved that the color change occurred in a visually noticeable way. This occurs due to prior freezing for freeze-drying in an ultra-freezer and the decrease in the water content of the product. It was concluded that porcine kidney has high nutritional value and has potential for inclusion in foods intended for humans and animals. However, pre-treatments for microbiological decontamination of the viscera are extremely important for future applications in the food industry, aiming for greater quality and utilization.