Estudo da secagem por aspersão de hidrolisados proteicos obtidos a partir de coprodutos do abate de suínos (Sus scrofa domesticus) e tilápia do Nilo (Oreochromis niloticus)

Abstract

The large volumes of waste generated from the slaughter of animals have led to the emergence of new methods and processes for the treatment and use of such waste, now called by-product, leading to new sources of revenue, preservation of the environment and development in meeting the demanding environmental laws. In this context, new technologies and processes for the production of by-products have been developed and made available to small businesses that, in general, do not proceed to the use of this waste, and so providing the use of the raw material in its entirety. The main goal of this work was to perform scientific studies in the animal slaughtering waste processing field, producing dehydrated protein hydrolysates with palatability and nutritional characteristics, seeking employment as animal feed. Swine liver (Sus scrofa domesticus) and slaughtering by-products of Nile Tilapia (Oreochromis niloticus) were used and subjected to an enzymatic hydrolysis process using the protease from Bacillus licheniformis (ALCALASE®) and subsequent spray drying process. A central composite non-factorial surface design 22 with four axial points was executed and inlet drying air temperature (Te in oC) and the ratio between liquid product feed and dryig air feed (Qp/Qar) were defined as factors. Response variables evaluated were moisture content (%), crude protein (%) and particle diameter (µm). The statistical study showed that the lower result for moisture (6,79%) for pork liver hydrolysate was obtained at high inlet air temperature (Te = 173 oC) and with higher fluxes of liquid product and air (Qp/Qar = 0,000207). The higher content for protein (72%) was obtained at a lower inlet temperature (Te=137 oC), but with the same ratio that provided the lower result for moisture. The smallest particle diameter (D=18,18 µm) resulted from the combination of central point temperature (Te=155 oC) with the highest fluxes of product feed and air (Qp/Qar=0,000217). For the tilapia hydrolysate, the lower moisture content (9,68%) was also obtained with Te=173 oC, but with lower air and product feeds (Qp/Qar=0,000188). The highest crude protein content (86,15%) resulted from the highest temperature (180 oC) associated with central point fluxes (Qp/Qar=0,000206). It was not possible to evaluate particle diameter for the tilapia samples, once they were out of the Mastersizer equipment range. The isoterms were adjusted for four models (Langmuir, BET, Chung & Pfost e GAB) at three tmperatures (20, 35 e 50 oC), being the best results for both hydrolysates obtained with the Chung & Pfost model, with R2=0,984 for swine liver and R2=0,967 for tilapia. The product obtained is a high nutritional product for use in animal feed compounds that may contribute significantly to the upgrading and development of new products with industrial applications, providing an environmentally clean destination to the waste of the slaughterhouses, generating a final product of high aggregate value and enabling the generation of new sources of revenue.