Development of new deer (cervus elaphus) meat productsevaluation of the physicochemical parameters, chemical composition, volatile compounds, sensorial attributes, and shelf-life

Resum

This doctoral thesis aimed to provide scientific information about the development of new deer meat products and the application of food reformulation strategies based on salt/animal fat partial or total replacement, to evaluate their effects on some meat products. Specifically, five products were elaborated: dry-cured deer loin, deer pâté, deer burger, dry-cured deer sausage, and dry-cured deer cecina. Except for the sensory attributes for dry-cured loins and the TBARS for sausages, all the products were analysed for pH, colour (Lightness - L*, Redness - a*, and Yellowness - b*), texture, TBARS, proximate composition, and sensory attributes. In addition, for the dry-cured loins, sausages, and cecinas the volatile compounds (VOCs) profile was determined, meanwhile, in burgers the water holding capacity was analysed. For the elaboration of the deer products, all meat cuts were obtained from carcasses of Iberian red deer (Cervus elaphus) from Cárnicas Dibe (Cáceres, Spain). The meat cuts were vacuum packed and transported refrigerated to the Centro Tecnolóxico da Carne (CTC) (San Cibrao das Viñas, Spain). The dry-cured loins were prepared with NaNO3, NaNO2, NaCl and condiments, and they were analysed on days 0, 30, and 60 of the processing. For the pâté manufacture four different batches were elaborated according to the fat source: 100% of pork back fat (control) or 50% of pork back fat replaced by 50% of microencapsulated oils (tiger nut or chia or linseed). Concerning the deer burgers and the dry-cured deer sausages, the animal fat was replaced by vegetable oils emulsion with alginate-based hydrogels. The burgers were manufactured according to their fat source in four batches: 100% of pork back fat (control), 100% of tiger nut oil, 100% of chia oil, and 100% of linseed oil. Assessments were performed on days 0, 6, 12, and 18 of storage. Regarding the dry-cured sausages, four different batches were prepared based on the fat source: 100% of pork back fat (control) or 50% of pork back fat replaced by olive oil or canola oil or soy oil. Samples were assessed after 45 days of processing. To elaborate the dry-cured deer cecina, meat pieces were brined with different salt mixtures: 100% NaCl (control), 30% NaCl and 70% KCl (SMI), and 30% NaCl, 50% KCl, 15% CaCl2, and 5% MgCl2 (SMII). At the end of processing, cecinas were analysed. Concerning the results obtained in the present study, dry-cured deer loin showed during the processing a decrease in the colour parameters and an increase in texture and TBARS values meanwhile fat, protein, and ash remained constant. The lipolysis and proteolysis reactions and the content of VOCs were directly related. Regarding pâtés, all the modified batches presented lower texture values. In addition, despite chia and linseed batches meeting the dietary reference intakes (DRIs) for the fatty acids, they also displayed higher susceptibility to oxidation, and lower values in the acceptance test compared to the control. Considering burgers, texture results were positive, since no significant (P > 0.05) differences were identified among treatments. All reformulated batches could be labelled as "low-fat" burgers. Moreover, chia and linseed treatments improved the polyunsaturated fatty acids (PUFA) content of the burgers by reducing saturated fatty acids (SFA) compared to control. In respect of sensory analysis, tiger nut and linseed treatments did not show significant (P > 0.05) differences with control in the acceptance test. Concerning the dry-fermented sausages, the alternative treatments with olive, canola, and soy oils affected the VOCs profile, which influenced the sensory attributes of the products. The sensory analysis indicated that the soy oil batch presented the highest values in the acceptance and preference tests. Finally, the analyses of the cecina did not demonstrate a significant (P > 0.05) effect of the treatments on moisture, fat, protein, texture, colour, and total fatty acids. On the other hand, differences (P < 0.001) were identified in the content of total VOCs. The sensory analysis indicated that SMII treatment modified the acceptance while control and SMI did not differ (P > 0.05) between them. Lastly, our study allowed us to conclude that deer meat showed the potential to be utilized by the food industry to elaborate healthier meat-based products. Dry-cured loin and all burgers and cecinas` treatments showed lower values for fat than those DRIs suggested by international agencies. In addition, chia and linseed batches of pâtés and burgers presented a healthy n-6/n-3 ratio (< 2).