IMPROVING THE MEAT QUALITY OF BLESBOK (DAMALISCUS DORCAS PHILLIPSI) AND SPRINGBOK (ANTIDORCAS MARSUPIALIS) THROUGH ENHANCEMENT WITH INORGANIC SALTS By PETRO-MARÈ DU BUISSON Thesis presented in partial fulfilment of the requirements for the degree of MASTERS OF SCIENCE IN ANIMAL SCIENCES (Meat Science) at the University of Stellenbosch Study Supervisor: Prof. L.C. Hoffman April 2006 Stellenbosch Declaration I, the undersigned, hereby declare that the work contained in this thesis is my own original work and that I have not previously, in its entirety or in part, submitted it at any university for a degree. Signature:……………………………. Date:………………………………….. ii Abstract This research had a dual purpose, firstly to study five muscles (M. biceps femoris, M. longissimus et lumborum, M. rectus femoris, M. semitendinosus and M. supraspinatus) of the blesbok (Damaliscus dorcas phillipsi) and springbok (Antidorcas marsupialis) in terms of the physical and chemical meat quality characteristics, and secondly, to investigate the effects of inorganic salt enhancement on the physical, chemical and sensory meat quality characteristics. The muscles differed significantly for the investigated characteristics, with the exception of a* value, chroma, and ash percentage, which did not differ in either blesbok or springbok. Furthermore, no muscle differences were found in fat percentage in blesbok or protein percentage in springbok meat. Muscle differences were found in the stearic acid (C18:0) composition, the percentage saturated fatty acids (SF) and the polyunsaturated: saturated fatty acid ratio (P:S) of the blesbok. Only linoleic acid (C18:2) as a percentage of the total fatty acids differed significantly amongst the springbok muscles. The shear force values were found to be significantly lower in the enhanced samples (blesbok: 25.16 vs. 43.75 N/1.27cm; and springbok: 23.96 vs. 34.89 N/1.27cm), which means that the enhanced muscles were more tender. The enhanced muscles of both species were found to have lower values for all investigated colour characteristics. Moisture values were found to be higher in all the enhanced muscles (blesbok: 76.53% vs. 74.38%; and springbok: 75.34% vs. 73.37%). The lower fat and protein contents of the enhanced muscles can possibly be ascribed to a diluent effect caused by the water added as part of the inorganic salt injection (blesbok: fat, 1.86% vs. 2.22%, protein, 19.61% vs. 21.67%; and springbok: fat, 1.84% vs. 2.14%, protein, 21.23% vs. 23.26%). Major changes in the mineral contents were expected between the two treatments and in both species the enhanced muscles had higher phosphorus, potassium, sodium and copper values, but lower magnesium, iron and zinc levels than the untreated muscles. Analytical sensory analyses were performed on the M. biceps femoris and M. longissimus et lumborum samples of both species. Tenderness and juiciness were significantly higher in the enhanced muscles. Although salty taste was significantly higher in the enhanced muscles due to the addition of the inorganic salt solution, it remained acceptable. Analytical and consumer sensory analyses were performed on blesbok and springbok M. longissimus et lumborum samples prepared in a stock mixture. The outcome of the analytical sensory analysis was similar to the analytical results reported above. The consumer sensory iii Abstract analysis showed that consumers preferred the enhanced blesbok and springbok muscles, with a significant improvement in consumers’ likeness of enhanced vs. untreated meat. This study provides important insights into the muscle differences of two of the most common game species currently utilised in South African meat production. It confirms that both species can be marketed as a low fat organic red meat source well capable of filling the modern consumer’s nutritional and health needs. It also shows that enhancing game meat with an inorganic salt solution might be a very useful processing tool to use to further game meat acceptability in terms of tenderness and juiciness as game meat is often experienced as being dry and less tender because of its lower fat content and the use of incorrect preparation techniques. iv Opsomming Hierdie navorsing het ‘n tweeledige doel, eerstens om die vyf spiere (M. biceps femoris, M. longissimus et lumborum, M. rectus femoris, M. semitendinosus en M. supraspinatus) van die blesbok (Damaliscus dorcas phillipsi) en die springbok (Antidorcas marsupialis) in terme van die fisiese en chemiese eienskappe van vleiskwaliteit te bestudeer, en tweedens, om die effek van ‘n anorganiese sout oplossing op die fisiese, chemiese en sensories kwaliteitseienskappe te ondersoek. Die spiere het betekenisvol verskil vir die meeste van die kwaliteitseienskappe, met die uitsondering van die a* waarde, chroma en as-persentasie, waarvoor daar geen verskille by die blesbok of die springbok was nie. Verder is daar ook geen spierverskille in die vet persentasie in blesbok of in die persentasie proteïene in springbokvleis gevind nie. Spier verskille is gevind in die steariensuur (C18:0) samestelling, die persentasie versadigde vetsure (SF) en die poli-onversadigde: versadigde vetsuur ratio (P:S) van die blesbok. Slegs linoleïensuur (C18:2) as persentasie van die totale vetsure het betekenisvol verskil tussen die springbok spiere. Die skeurkrag waardes was betekenisvol laer in die behandelde monsters (blesbok: 25.16 vs. 43.75 N/1.27cm; en springbok: 23.96 vs. 34.89 N/1.27cm), wat beteken dat die behandelde spiere sagter was. Die behandelde spiere van beide spesies het laer waardes getoon vir alle kleur eienskappe wat ondersoek is. Vog waardes was hoër in al die behandelde spiere (blesbok: 76.53% vs. 74.38%; en springbok: 75.34% vs. 73.37%). Die laer vet en proteïen inhoud in die behandelde spiere kan waarskynlik verklaar word deur die verdunningseffek wat veroorsaak is deur die water wat bygevoeg is as deel van die anorganiese sout-inspuiting (blesbok: vet, 1.86% vs. 2.22%, proteïen, 19.61% vs. 21.67%; en springbok: vet, 1.84% vs. 2.14%, proteïen, 21.23% vs. 23.26%). Groot veranderinge is verwag in die mineraal inhoud van die twee behandelinge en in beide spesies het die behandelde spiere hoër fosfor, kalium, natrium en koper waardes en laer magnesium, yster en sink waardes as die onbehandelde spiere getoon. Analitiese sensoriese analises is op die M. biceps femoris en M. longissimus et lumborum monsters van beide spesies uitgevoer. Sagtheid en sappigheid was betekenisvol hoër in die behandelde spiere. Alhoewel souterige smaak betekenisvol hoër was in die behandelde spiere as gevolg van die byvoeging van die anorganiese sout oplossing, was dit steeds aanvaarbaar. v Opsomming Analitiese en verbruiker sensoriese analises is uitgevoer op blesbok en springbok M. longissimus et lumborum monsters wat in ‘n aftreksel voorberei is. Die uitkoms van die analitiese sensoriese analise was soortgelyk aan die bogenoemde gerapporteerde analitiese resultate. Die verbruikers sensoriese analise het getoon dat verbruikers die behandelde blesbok en springbok spiere verkies, met ‘n betekenisvolle verbetering in die hoeveelheid waarvan verbruikers van die behandelde, eerder as die onbehandelde vleis, gehou het. Hierdie studie lewer belangrike insigte in die spierverskille van twee van die mees algemene wild species wat op die oomblik in Suid-Afrikaanse vleisproduksie benut word. Dit bevestig dat beide blesbok and springbok bemark kan word as ‘n bron van lae vet, organiese rooivleis wat uiters geskik is om aan die moderne verbruiker se voedings- en gesondheidsbehoeftes te voldoen. Dit wys ook dat die behandeling van wildsvleis met ‘n anorganiese sout oplossing moontlik ’n baie bruikbare prosesseringsmetode is om die aanvaarbaarheid van wildsvleis in terme van sagtheid en sappigheid te verbeter, aangesien wildsvleis dikwels as droog en minder sag ondervind word as gevolg van die laer vet inhoud en foutiewe voorbereidingstegnieke. vi Acknowledgements I wish to sincerely express my appreciation to the following people and institutions: Prof. L.C. Hoffman, for his invaluable knowledge and guidance throughout this project. Freddy Hirsch, for providing technical assistance and the inorganic salt solution. The Department of Tourism, Environmental and Economic affairs (Free State Province) for the procurement of animals. The Department of Animal Sciences, for technical, as well as statistical assistance. The Department of Consumer Sciences, for providing the sensory laboratory and consumer sensory locales and for their assistance in the execution of the sensory tests. Family and friends, for their support and encouragement throughout this project. vii Notes The language and style used in this thesis are in accordance with the requirements of the scientific journal, Meat Science. This thesis represents a compilation of manuscripts where each chapter is an individual entity and therefore, some repetition between chapters may occur. Results from this study have been presented at the following congress: du Buisson, P. & Hoffman, L.C. (2004). Tender Springbok – we did it! The 2nd Joint Congress of the Grassland Society of Southern African and South African Society of Animal Science. Goudini Spa (28 June – 1 July). du Buisson, P. & Hoffman, L.C. (2004). Improving the eating quality of Blesbok meat by injecting an inorganic salt mixture. The 2nd Joint Congress of the Grassland Society of Southern African and South African Society of Animal Science. Goudini Spa (28 June – 1July). viii Table of contents Chapter Page 1. Introduction…………………………………………………………….