1. New insights in brewer spent yeast extract used as gel stabilizer in cooked ham production Gastón Ignacio Pancrazio 1,2¨* (gpancrazio@fb.uner.edu.ar); Sara Cunha 2 ; Paula Guedes de Pinho 3 ; Isabel Maria Pinto Leite Viegas Oliveira Ferreira 2 ; Olívia Maria de Casto Pinho 1,2 1 Faculdade de Ciências da Nutrição e Alimentação, Universidade do Porto, Porto, Portugal. 2 REQUIMTE, Laboratório de Bromatologia e Hidrologia, Departamento de Ciências Químicas, Faculdade de Farmácia, Universidade do Porto, Porto, Portugal. 3 REQUIMTE, Departamento de Ciências Biológicas, Laboratório de Toxicologia, Faculdade de Farmácia, Universidade do Porto, Porto, Portugal. Introduction Results and Discussion Methods Conclusions Spent Saccharomyces yeast extract obtained from brewing industry yeast by- product was tested as a food ingredient. This new ingredient can be used to reduce tumbling time in cooked ham production maintaining the physical, chemical and sensorial characteristics of high quality conventional cooked ham. The higher hardness of cooked ham added with yeast extract is explained by the higher protein content and denaturation due to heat action that strength the gel formed during cooking and improves the textural characteristics of cooked ham. According with this study, spent yeast extract could be used as gel stabilizer in cooked ham formulations and with main emphasis in cooked ham productions where the processing time is an important goal for food industry producers. Yeast extracts have received much attention as flavour enhancers in low-sodium fermented sausages, in low-sodium cured meat products and such as sauces, gravies, soups, chips and crackers [ 1,2 ]. Cooked ham is a very common brine-treated product consumed worldwide. Brine promotes protein solubilisation, increases flavour and uniform distribution of other ingredients (i.e. sugars, spices, polyphosphates, etc.). Tumbling is important to distribute the brine into muscle and promote cellular disruption. Cooking can be considered as pasteurization, since internal temperature of the ham reaches between 69-72ºC for 30 to 60 minutes [3]. During the past years, there has been an economic incentive to use high-protein non-meat additives to decrease production costs. However, no studies are described concerning the use of protein rich extracts from spent yeast biomass from brewing industry on production of cooked ham. Brewer’s Saccharomyces yeast biomass is the second major by-product from beer industry, its extracts can be valorised as food ingredients due to its content in proteins, nucleotides, minerals and vitamins [4]. Thus, the goal of this study was the used of brewer spent yeast extract as gel stabilizers in cooked ham production with reduce tumbling time and maintain its high quality characteristics. Were evaluated physical-chemical and sensory characteristics of different cooked hams: conventional product; samples with reduced tumbling time and with addition of brewing spent yeast extract. Instrumental measurable parameters and sensory analyses were performed at the beginning and end of shelf- life.. Washed (1:3 H2Od) Centrifugated (10,000g, 4°C, 5 min) x3 Centrifugated (15,000g, 4°C, 30 min) Biomass Acetate Buffer 0.04M 1 min +1min in ice 1 min +1min in ice x10 Lyoph. + 250ml Spent Yeast Extract Sampling n= 16 12 days n= 16 9 h of Tumbling Pork Meat - 40 kg Pork leg cuts - 20 kg Injected (35% brine/ meat v/w) 1 % v/w of acetate Buffer 0.04 M 1% v/w of Spent yeast extract in 0.04 M acetate buffer Cooking step Cooling step overnight 0-4°C Cooked ham added with spent yeast n=8 Cooked ham added with acetate buffer n=8 Cooked ham added with spent yeast n=8 Cooked ham added with acetate buffer n=8 90 days 1.5 h 2 h 2.5 h 3 h 1.5 h 2 h 2.5 h 3 h n= 4 Lote 1 Lote 2 n= 32 Figure 2 shows TPA attributes (hardness, gumminess and chewiness) and L*, a* and b* values of CT, RT, RTY cooked hams analysed at 12 and 90 days. ANOVA indicates that similar results were observed between CT and RTY at 12 days while RT cooked hams presented significantly lower texture parameters when compared with RTY, but no significant differences were observed between CT and RT (Figure 2A). After 90 days of storage (Figure 2 B) CT and RTY presented similar texture, whereas lower values were observed in RT. The results highlight that reducing tumbling decreases hardness, gumminess and chewiness of cooked ham, but this effect can be avoided by the addition of spent yeast extract. Lower differences were observed concerning colour attributes Determinations FAA MTBTFSA - GC/MSMS PROTEOLYSIS - HPLC COLOUR AND TEXTURE Nutritional composition and pH of CT, RT and TRY cooked hams is presented in Table 1. Sodium content ranged between 0.69 to 0.73 g/100 g and potassium varied between 0.32 and 0.35 g/100 g of cooked ham. Na + values were lower than those reported by other authors that describe mean values of 2.79 g/100 g [5] and 2.1 g/100 g [6]. K + values were also lower than those described by Cardoso and others 2013 who reported that cooked ham had K + contained 0.42 g/100g. Acknowledgements: This work received financial support from PEst-C/EQB/LA0006/2011. Authors thank Unicer for supplying raw material. References: [1]Desmond, E. (2006). "Reducing salt: A challenge for the meat industry." Meat Science 74(1): 188-196. [2] Campagnol, P. C. B., B. A. dos Santos, R. Wagner, N. N. Terra and M. A. R. Pollonio (2011). "The effect of yeast extract addition on quality of fermented sausages at low NaCl content." Meat Science 87(3): 290-298. [3] Toldrá, F., L. Mora and M. Flores (2010). Cooked Ham. Handbook of Meat Processing, Wiley-Blackwell: 299-311. [4] Ferreira, I. M. P. L. V. O., O. Pinho, E. Vieira and J. G. Tavarela (2010). "Brewer's Saccharomyces yeast biomass: characteristics and potential applications." Trends in Food Science and Technology 21(2): 77-84. [5] Válková, V., A. Saláková, H. Buchtová and B. Tremlová (2007). "Chemical, instrumental and sensory characteristics of cooked pork ham." Meat Science 77(4): 608-615. [6] Cassidy, R. O., H. W. Ockerman, B. Krol, P. S. Van Roon, R. F. Plimpton and V. R. Cahill (1978). "Effect of tumbling method, phosphate level and final cook temperature on histological characteristics of tumbled porcine muscle tissue." Journal of Food Science 43(5): 1514-1518.