The effect of a fat replacer on the physical, chemical, microbiological and sensory characteristics of blesbok (Damaliscus pygargus phillipsi) cabanossi

Mitchell, Cecil Starr (2015-12)

Thesis (MSc Food Sc)--Stellenbosch University, 2015.

Thesis

ENGLISH ABSTRACT: Processed meat products usually have a high fat content and health conscious consumers tend to find this unacceptable. Traditional processed meat products, such as cabanossi, are furthermore produced with animal fat that contain high levels of saturated fatty acids (SFA). A diet high in SFA may pose health risks. There are vegetable oils that could provide a better fatty acid profile in meat products and could be used as fat replacers. Unfortunately, reformulation may affect the processed meat product’s characteristics and this could easily decrease a product’s market viability. This study was conducted to investigate the effect of a canola oil-based fat replacer in the form of a protein-based hydrocolloid gel (FR) at three concentrations, i.e. 10% (FR1), 20% (FR2) and 30% (FR3) with no pork back fat added, compared to the Control containing pork back fat on the physical, chemical, microbiological and sensory characteristics of blesbok (Damaliscus pygargus phillipsi) cabanossi. The proximate analysis of all three FR treatments had higher (P ≤ 0.05) moisture, protein and ash content than the Control and as expected, the fat content was lower (P ≤ 0.05) in all three FR treatments. The lipid oxidation results were lower than expected with no difference (P > 0.05) between the Control and all three FR treatments; possibly due to the nitrates’ antioxidant ability. The fatty acid composition did not differ (P > 0.05) at day 0 as well as after 60 days storage, however, the fatty acid composition for the treatments at day 0 and day 60 differed (P ≤ 0.05). At day 0 and day 60, FR2 and FR3 had larger (P ≤ 0.05) PUFA:SFA ratios (0.8-1.0) than the Control and FR1. Furthermore at day 0 and day 60, all three FR treatments had lower (P ≤ 0.05) n-6:n-3 ratios (2.8-3.1) than the Control. Descriptive sensory analysis was performed alongside an instrumental texture analysis to profile any changes in the cabanossi’s characteristics (aroma, appearance, flavour and texture). The trained panel detected differences in all the characteristics between the Control and the three FR treatments, as well as differences between the three FR treatments. An unexpected bitter taste developed after 60 days storage, maintained at 4°C; however, there was no sign of rancidity development, as perceived by the sensory panel. In terms of physical characteristics at day 0 and day 60, the Control and FR1 differed (P ≤ 0.05) from FR2 and FR3 with the latter scoring the lowest (P ≤ 0.05) in instrumental hardness. Microbiological quality must be in accordance with the country’s legislation. Testing for Staphylococcus aureus, Listeria monocytogenes, Salmonella spp., coliforms and aerobic forming bacteria was conducted. At day 0 and after 60 days storage, maintained at 4°C; the Control and all three FR treatments were in accordance with various regulations and food safety guidelines from South Africa and several international specifications. The fat content was successfully decreased by ~20% with an improved fatty acid profile and a limited lipid oxidation. The sensory and physical properties were easily discernible between the Control and the three FR treatments. The animal fat used in the control had certain characteristics which the fat replacer was not able to mimic. In addition, during storage (60 days) a bitter taste developed in the three FR treatments which were undesirable. All the treatments were microbiologically safe and were in accordance with local, South Africa, and international regulations. The FR treatments were noticeably different to the Control however, a lower fat content, improved fatty acid profile and a 60 day shelf-life were achieved. The results have added more knowledge about fat replacers in processed meat products especially with regard to cabanossi.

AFRIKAANSE OPSOMMING: Geprosesseerde vleisprodukte is bekend vir ‘n hoë vetinhoud en word daarom gereeld deur gesondheidsbewuste verbruikers as onaanvaarbaar beskou. Vleisprodukte soos cabanossi word tradisioneel van diervet gemaak en bevat dus ‘n hoë vlak versadigde vet (SFA). Aangesien ‘n dieet hoog in versadigde vet mag lei tot gesondheidsimplikasies kan sekere plantolies gebruik word as vetvervanger, om sodoende ‘n meer gewenste vetsuurprofiel te verseker. Herformulasie van so ‘n aard mag egter verandering in die eienskappe van die produk teweegbring en dus ook die haalbaarheid daarvan beïnvloed. Hierdie studie is uitgevoer om die effek van 'n vetvervanger met ʼn kanola-olie basis in die vorm van 'n proteïen-gebaseerde hidrokolloïde jel (FR) te ondersoek op die fisiese, chemiese, mikrobiologiese en sensoriese eienskappe van blesbok (Damaliscus pygargus Phillipsi) cabanossi. Die eksperimentele monsters het bestaan uit by drie konsentrasies FR, nl. 10% (FR1), 20% (FR2) en 30% (FR3), en geen varkvet, terwyl die Kontrole monster varkvet en derhalwe geen FR bevat het nie. In die eerste studie (Hoofstuk 3) is proksimale analise, lipied oksidasie en die vetsuursamestelling bepaal. Die drie FR behandelings het hoër (P ≤ 0.05) vog, proteïen en asinhoud as die Kontrole gehad en, soos verwag, was hul vetinhoud ook laer (P ≤ 0.05). Die lipied oksidasie resultate was laer as wat verwag is met geen verskil (P > 0.05) tussen die Kontrole en die drie FR behandelings nie; moontlik as gevolg van die bygevoegde nitrate se vermoë om as anti-oksidant op te tree. Die vetsuursamestelling per behandeling het nie verskil (P > 0.05) op dag 0 en na 60 dae by 4°C nie, maar dit het wel op dag 0 en dag 60 tussen die Kontrole en die drie FR behandelings verskil (P ≤ 0.05). Vetsuurverhoudings, veral die omega-6:omega-3 (n-6:n-3) verhouding, is ʼn aanduiding van die voedingswaarde van dieetvet. Op dag 0 en dag 60 het FR2 en FR3 groter (P ≤ 0.05) POVS:VVS verhoudings (0.8-1.0) as die Kontrole en FR1 gehad. Verder, op dag 0 en dag 60 het al drie FR behandelings laer (P ≤ 0.05) n-6:n-3 verhoudings (2.8-3.1) as die Kontrole gehad. Die fisiese en sensoriese eienskappe is belangrik vir die sukses van ʼn produk. In die tweede eksperimentele studie (Hoofstuk 4) is ʼn beskrywende sensoriese analise saam met 'n instrumentele tekstuur-analise uitgevoer. Die opgeleide paneel het betekenisvolle verskille tussen die Kontrole en die drie FR behandelings opgetel, asook verskille tussen die drie FR behandelings. Daar het ʼn onverwagse “Bitter smaak” na 60 dae se berging by 4°C ontwikkel, alhoewel die sensoriese paneel geen teken van galsterigheid waargeneem het nie. In terme van fisiese eienskappe op dag 0 en dag 60, het die Kontrole en FR1 verskil (P ≤ 0.05) van FR2 en FR3, waar laasgenoemde die laagste (P ≤ 0.05) vir instrumentele hardheid (Inst. Hardheid) gehad het. Alhoewel die vet-vervangde cabanossi gesond moet wees en oor ʼn wenslike sensoriese profiel beskik, moet die mikrobiologiese gehalte ook in ooreenstemming met Suid-Afrika se wetgewing wees. In die derde studie (Hoofstuk 5) was ʼn mikrobiologiese analise uitgevoer om te toets vir Staphylococcus aureus, Listeria monocytogenes, Salmonella spp., Kolivorme en aërobiese vormende bakterieë. Op dag 0 en na 60 dae se berging by 4°C was die Kontrole en al drie FR behandelings in ooreenstemming met verskillende Suid-Afrikaanse regulasies en hul riglyne vir voedselveiligheid, asook verskeie internasionale spesifikasies. Daarom kan die produk geag word as veilig om te eet wanneer dit vir 60 dae by 4°C geberg word. Vanuit hierdie resultate kan dit afgelei word dat die vet van blesbok (Damaliscus pygargus Phillipsi) cabanossi met 'n proteïen-hidrokolloïde jel, wat kanola-olie bevat, suksesvol vervang kan word. Dit het gunstige proksimale resultate, 'n verlaagde vetinhoud en is mikrobiologies veilig vir 'n bergingstydperk van 60 dae by 4°C. Die studie het getoon dat die vetinhoud van geprosesseerde cabanossi suksesvol verlaag kan word met ~20%. Tesame hiermee het die vetvervanging ook gelei tot ‘n meer onversadigde vetsuur profiel met ‘n beperkte hoeveelheid lipied oksidasie wat plaasgevind het. Die verskille tussen die sensoriese en fisiese eienskappe van die kontrole en die FR behandelings was duidelik opletbaar. Die gebruik van diervet in die kontrole produk is verantwoordelik vir sekere eienskappe wat die vetvervanger nie kon naboots nie. Verder het ‘n ongewensde, bitter smaak ontwikkel in die FR behandelings gedurende die stoor tydperk. Alle behandelings was mikrobiologies veilig en in akkoord met die Suid Afrikaanse asook internasionale regulasies. Die resultate van die studie dra by tot ‘n beter begrip van die gebruik van vetvervangers in geprosesseerde vleisprodukte, veral met betrekking tot cabanossi.

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