Factors influencing colour variation and oxidative stability of South African game meat species

Neethling, Nikki Elrita (2016-03)

Thesis

ENGLISH ABSTRACT: It is believed by many that the future of South African game farming depends on the development of a sustainable game meat industry. To develop such an industry, game meat products of consistently high quality must be supplied to consumers. To ensure the quality and consistency of these meat products, standard processing guidelines are required. No such guidelines are currently available and research on meat quality of South African game meat is thus required to establish these guidelines. There is currently only limited research available on the meat quality of game meat. Meat colour is important as it is the sole quality factor which consumers can use at the time of purchasing to select meat. Consumers prefer meat which is bright red in colour as they perceive it to be fresher, more wholesome and of higher quality than discoloured meat. Discoloured meat is often discounted, resulting in a loss of profits. Thus, maintaining the bright red colour of meat is essential in ensuring maximum profits. Colour stability is thus an important meat quality attribute which must be examined. Currently no research exists regarding the colour stability of South African game species. The colour stability of three major South African game species, blesbok (Damaliscus pygargus phillipsi), springbok (Antidorcas marsupialis) and fallow deer (Dama dama) were evaluated by measuring surface colour attributes (L*, a*, b*, hue, chroma and R (630/580)), surface myoglobin redox forms (percentage deoxymyoglobin, percentage oxymyoglobin and percentage metmyoglobin) and various biochemical attributes (pH, metmyoglobin reducing activity, oxygen consumption, thiobarbituric acid reactive substances, total, heme and non heme iron and total myoglobin) of three muscles, the infraspinatus (IS), longissimus thoracis et lumborum (LTL) and biceps femoris (BF) over an eight day colour stability trial at 2°C. The data indicated that the IS was the most colour stable of the three muscles for all the game species. For both the blesbok and fallow deer, the LTL was observed to be marginally more colour stable than the BF, whereas the LTL and BF for the springbok were observed to have similar colour stabilities. Overall the colour stability of the IS was determined to be eight days or more and that of the LTL and BF only one day for all three game species. Although significant gender differences were observed for the colour stability data, these were disregarded as no gender differences were visually perceived. Despite the similarities in colour stabilities noted for the muscles of the three game species, species differences were observed for various of the surface and biochemical attributes highlighting the need for both muscle and species specific processing strategies to improve colour stability of game meat. This study provided baseline data for the colour stability of game meat, specifically springbok, blesbok and fallow deer. It also highlighted the vast amount of research that is still required to ensure that the colour stability of game meat is optimised to ensure maximum colour stability.

AFRIKAANSE OPSOMMING: Daar word deur baie geglo dat Suid-Afrikaanse wildboerdery se toekoms van die ontwikkeling van ‘n volhoubare wildsvleis mark afhang. Om so ‘n mark te ontwikkel, moet vleisprodukte van hoë gehalte konsekwent aan verbruikers voorsien word. In orde om die kwaliteit en konsekwentheid van sulke vleisprodukte te verseker, word standaard prosesseringsriglyne benodig. Geen sulke riglyne is tans beskikbaar nie en navorsing op die kwaliteit van Suid-Afrikaanse wildsvleis word dus benodig om hierdie riglyne van stapel te stuur. Slegs ‘n beperkte hoeveelheid navorsing is tans op die vleiskwaliteit van wildvleis beskikbaar. Vleiskleur is baie belangrik aangesien dit die enigste kwaliteitsfaktor is wat verbruikers tydens aankoop kan benut om vleis te kies. Verbruikers verkies vleis wat helder rooi van kleur is aangesien hulle dit as varser, meer voedsaam en van hoër kwaliteit as bruinverkleurde vleis ag. Die prys van verkleurde vleis word dikwels deur handelaars afgemerk wat tot ‘n verlies in wins lei en daarom speel die behoud van vleis se helder rooi kleur ‘n sleutel rol in die maksimering van winste. Kleurstabiliteit is dus ‘n belangrike vleiskwaliteit kenmerk wat ondersoek moet word. Geen navorsing is tans op die kleurstabiliteit van Suid-Afrikaanse wildspesies beskikbaar nie. Die kleurstabiliteit van drie gewilde Suid-Afrikaanse wildspesies, blesbok (Damaliscus pygargus phillipsi), springbok (Antidorcas marsupialis) en takbok (Dama dama), was ge-evalueer deur die eienskappe van oppervlak kleur (L*, a*, b*, hue, chroma en R (630/580)), oppervlak mioglobien redoks staat (persentasie deoksimioglobien, persentasie oksimioglobien en persentasie metmioglobien) sowel as verskeie biochemiese eienskappe (pH, metmioglobien verminderings aktiwiteit, verbruik koers van suurstof, Tiobarbitiensuur suur reaktiewe stowwe, totale heme en nie-heme yster en totale mioglobien) van drie spiere, die infraspinatus (IS), longissimus thoracis et lumborum (LTL) en biceps femoris (BF), oor ‘n agt dae kleurstabiliteits proefloop by 2°C te meet. Die data het getoon dat die kleurstabiliteit van die IS die beste van die drie spiere vir al die spesies was. Vir beide blesbok en takbok is dit waargeneem dat die LTL effens meer kleurstabiel as die BF was. Vir springbok daarenteen is dit waargeneem dat beide die LTL en BF soortgelyke kleurstabiliteit getoon het. Vir al drie wildspesies is dit vasgestel dat die kleurstabiliteit vir die IS agt dae of langer en vir die LTL en BF slegs een dag was. Hoewel beduidende geslagsverskille in die kleurstabiliteit data waargeneem is, is dit verontagsaam aangesien dit nie visueel waargeneem kon word nie. Ongeag die ooreenkomste opgemerk in die kleurstabiliteit van die spiere vir die drie wildspesies, is verskille vir verskeie oppervlak en biochemiese eienskappe tussen die verskillende spesies opgemerk wat die noodsaaklikheid vir beide spier en spesie spesifieke prosesserings strategië aandui om die kleurstabiliteit van wildsvleis te verbeter. Riglyn data vir kleurstabiliteit van wildsvleis, spesifiek springbok, blesbok en takbok, is in hierdie studie voorsien. Dit het ook die groot hoeveelheid navorsing wat steeds benodig word om te verseker dat kleurstabiliteit van wildsvleis geoptimeer word om maksimum kleurstabiliteit te verseker beklemtoon.

Please refer to this item in SUNScholar by using the following persistent URL: http://hdl.handle.net/10019.1/98555
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