Utilisation of pork rind and soya protein in the production of polony

Thesis (MSc Food Sc)--University of Stellenbosch, 2011.

ENGLISH ABSTRACT: The purpose of this study was to determine whether acceptable polony can be manufactured with varying quantities of chicken mechanically recovered meat (MRM), soya flour and pork rind to a fixed protein content of 10%, irrespective of fat content and without the addition of more fat to obtain a total meat equivalent (TME) of 75%. The effect of replacing MRM with soya and rind on the chemical, physical and sensory characteristics of polony was measured. The cost of producing each treatment by using the varying ingredients was also calculated. Three levels of soya flour (0, 4 and 8%) were combined with three levels of pork rind (0, 8 and 16%) to formulate the nine treatments of polony (R0S0, R0S4, R0S8, R8S0, R8S4, R8S8, R16S0, R16S4 and R16S8, where R and S represents rind and soya, respectively). The cost of making the nine treatments varied from R4.54/kg to R2.91/kg, where the most expensive treatment was the one in which no replacement of MRM was done (R0S0) and the least expensive treatment was R16S8, where most MRM was substituted with rind (16%) and soya (8%). The chemical results showed that the protein content of the nine treatments varied between 9.7 and 10.5%. Fat and ash decreased while moisture and total collagen increased as more MRM was being replaced with increasing levels of soya, rind or combinations of them. The physical results indicated that L* and b* increased while a* decreased, resulting in treatment samples which were lighter, more yellow and less red in colour. Hardness and gumminess increased in samples singly replaced with 8% rind, 4% soya or their combination (R0S0, R0S4, R8S0 and R8S4), while they decreased in the rest of the treatments. Cohesiveness increased in all treatments with increasing levels of soya and rind except for the sample containing 16% rind and 8% soya (R16S8). The pH of treatments containing 0% soya increased with rind increase whereas those with 4% soya did not change. The lowest pH was for the sample with 16% rind and 8% soya (R16S8). Sliceability was used to determine the ease of cutting intact slices at slice thicknesses of 2 and 3 mm. The sliceability of polony treatments which exhibited good slicing characteristic ranged between 80 and 100% at both 2 mm and 3 mm slice thicknesses. Sliceability was poorest for the treatment with high levels of rind and soya (R16S8) at both 3 mm (40%) and 2 mm (0%). The water holding capacity (WHC) of all treatments improved, except for the treatments to which no rind and soya was added (R0S0) and the treatment in which MRM was replaced with 8% soya (R0S8). Sensory analyses results signified that pink colour, colour intensity, salty taste, flavours (garlic, polony and spicy) and firmness decreased while soya flavour, pasty and fatty mouthfeel increased with increasing levels of rind, soya or their combination. Coarse texture decreased as rind increased while it increased with an increase in soya levels. Only five treatments were employed for consumer analyses. The most preferred treatment was that with 0% rind and 0% soya (R0S0), while the sample with 0% rind and 8% soya (R0S8) was the least preferred. It can be concluded that the production of polony through the replacement of MRM with rind and soya flour is possible, but consumer preference results show that consumers like polony products which have low levels of soya (≤4%) and moderate levels of rind (≤8%). However, the negative effects of rind and soya in polony with high levels of soya and rind can be rectified by adding appropriate additives, as provided for by manufactured meat regulations.

AFRIKAANSE OPSOMMING: Die doel van hierdie studie was om vas te stel of wisselende hoeveelhede meganies herwonne hoendervleis, sojameel en swoerd gebruik kan word om aanvaarbare polonie te vervaardig met ʼn vaste proteïeninhoud van 10%, ongeag die vetinhoud, en sonder die byvoeging van meer vet om ʼn algehele vleisekwivalent van 75% te kry. Hiervoor is die uitwerking op die chemiese, fisiese en sintuiglike kenmerke van polonie gemeet wanneer meganies herwonne vleis (“mechanically recovered meat”, oftewel “MRM”) met soja en swoerd vervang word. Voorts is die produksiekoste van elke formule op grond van verskillende bestanddele bereken. Drie vlakke sojameel (0%, 4% en 8%) is met drie vlakke swoerd (0%, 8% en 16%) gekombineer om die nege polonieformules (R0S0, R0S4, R0S8, R8S0, R8S4, R8S8, R16S0, R16S4 en R16S8) te skep, waar R die swoerd (“rind”) en S die sojameel verteenwoordig. Die vervaardigingskoste van die nege formules wissel van R4,54/kg tot R2,91/kg: Die duurste formule was dié sonder enige MRM-vervanging (R0S0), en die goedkoopste waar die meeste MRM met swoerd en soja vervang is (R16S8). Die chemiese resultate toon dat die proteïninhoud vir die nege formules tussen 9,7% en 10,5% wissel. Vet en as het afgeneem en vog en algehele kollageen het toegeneem namate al hoe meer MRM met toenemende vlakke soja, swoerd of ʼn kombinasie daarvan vervang is. Fisiese resultate toon dat L* en b* met MRM-vervanging toegeneem het, terwyl a* afgeneem het, met ligter, geler en minder rooi monsters tot gevolg. Hardheid en taaiheid het toegeneem by monsters waar MRM stuksgewys met 8% swoerd, 4% soja of ʼn kombinasie daarvan vervang is (R0S0, R0S4, R8S0 en R8S4), terwyl dit by die res van die formules afgeneem het. Saamklewing het by alle formules met hoër vlakke soja en swoerd toegeneem, buiten by die monster met 16% swoerd en 8% soja (R16S8). Die pH van formules met 0% soja het toegeneem namate die swoerd vermeerder is, terwyl dié met 4% soja onveranderd gebly het. Die laagste pH is aangeteken by die monster met 16% swoerd en 8% soja (R16S8). Snybaarheid is bepaal aan die hand van die gemak waarmee skywe van onderskeidelik 2 mm en 3 mm dik gesny kon word. Goeie snybaarheid, met ander woorde tussen 80% en 100%, is aangeteken vir polonie wat in sowel 2 mm as 3 mm diktes gesny kon word. Snybaarheid was die swakste vir die formule met hoë vlakke swoerd en soja (R16S8), vir sowel die 3 mm (40%) as die 2 mm diktes (0%). Die waterhouvermoë het by alle formules verbeter, buiten by die formule waarby geen swoerd of soja gevoeg is nie (R0S0) en die formule waar MRM met 8% soja vervang is (R0S8). Die resultate van die sintuiglike ontledings dui daarop dat die pienk kleur, kleurdiepte, sout smaak, geure (knoffel, polonie en speserye) en fermheid afgeneem het, en die sojageur, deegagtige tekstuur sowel as die tekstuur op die tong toegeneem het namate meer swoerd, soja of ʼn kombinasie daarvan bygevoeg is. Grofheid van tekstuur het afgeneem namate die swoerd verminder is, terwyl dit weer toegeneem het met ʼn toename in soja. Slegs vyf formules is vir verbruikersontledings gebruik. Die gewildste formule was dié met 0% swoerd en 0% soja (R0S0), terwyl die monster met 0% swoerd en 8% soja (R0S8) die minste byval gevind het. Daar kan dus afgelei word dat polonieproduksie deur die vervanging van MRM met swoerd en sojameel moontlik is, hoewel die proetoetsresultate toon dat verbruikers polonieprodukte met lae sojavlakke (≤4%) en matige swoerdvlakke (≤8%) verkies. Tog kan die negatiewe uitwerking van groot hoeveelhede swoerd en soja in polonie reggestel word deur toepaslike bymiddels, waarvoor die regulasies oor verwerkte vleis voorsiening maak, by te voeg.

Masters