Effect of functional enzyme additives on the sensory and shelf-life properties of ready-to-eat breakfast cereals

Thesis (MScFoodSc)--Stellenbosch University, 2019.

ENGLISH ABSTRACT: The aim of this study was to test the sensory quality of a ready-to-eat breakfast cereal (RTEBC) fortified with two functional enzymes additives, i.e. Tolerase P® (TolP) and Tolerase L® (TolL), as well as the viability of these enzymes over a shelf-life period of 12 months. The purpose was also to establish whether fortification with Tolerase P® could enhance the mineral quality and, when using Tolerase L®, to determine the level of functional enzyme additives available to digest lactose for lactose intolerant individuals. Three independent experimental batches of a RTEBC (100 kg per batch) were produced, and sub-samples of each of three batches were treated with TolL, with TolP and the third sub-sample was left untreated and thus functioned as a control. When comparing the two treated samples with the unfortified RTEBC in terms of full sensory profile (aroma, flavour and mouthfeel attributes) over the shelf-life period, the sensory profile of the TolLand TolP-treated cereals were found to be comparable to that of the untreated control sample at the onset of shelf-life, as well as after 12 months of shelf-life. The sensory panel found that the fortified cereal samples did not differ significantly (P>0.05) from the unfortified cereal sample for the majority of the sensory characteristics, i.e. coarseness and toasted colour (dry cereal attributes) and toasted colour, malted aroma, toasted cereal flavour, sweet taste, bitter taste and mouthfeel (cereal attributes with added milk), indicating that the respective enzymes did not impact negatively on the sensory profile of this RTEBC during shelf-life. The minerals calcium, zinc and iron of the RTEBC fortified with TolP increased with 43.3%, 49.7% and 56.7%, respectively. This indicated the effectiveness of the functional enzyme TolP in the ready-to-eat breakfast cereal prior to consumption. Furthermore, the TolP content remained viable for a shelf-life period of 12 months. Based on the percentage activity of the functional enzyme in the base material, the enzyme activity of the TolL-treated RTEBC was found to be fully effective for a 9-month shelf-life period. These results will find invaluable application in product development and marketing of RTEBC. The results will also add significantly to scientific information regarding the feasibility of fortification of RTEBC, specifically the effectiveness of functional enzyme additives for lactose intolerant individuals or the provision of sustained mineral nutrition for individuals that consume RTEBC on a regular basis.

AFRIKAANSE OPSOMMING: The doel van die studie was om die sensoriese kwaliteit van ‘n kommersiële klaar-gaar ontbytgraan (KGOG), gefortifiseer met twee funksionele ensieme (Tolerase P® [TolP] en Tolerase L® [TolL]), te toets, asook om die effektiwiteit van die onderskeie ensieme tydens ‘n 12-maande rakleeftydstudie te bepaal. Verdere oogmerke was om vas te stel of TolPfortifikasie die mineraalinhoud van die KGOG sou verhoog en of TolL-fortifikasie tot genoegsame funksionele ensiemvlakke sal lei om laktose effektief te verteer in laktoseintolerante individue. Drie onafhanklike eksperimentele produksielotte KGOG is vir die studie geproduseer (100 kg per lot), waarna elke lot in drie gedeel is. Die eerste sub-lot is met die funksionele ensiem TolL behandel en die tweede sub-lot met TolP. Die derde sub-lot is met geen ensiem behandel nie en het dus gedien as ‘n kontrole. Na ‘n rakleeftydstudie van 12 maande het beide die behandelde en onbehandelde behandelings nie betekenisvol (P>0.05) van mekaar verskil in terme van sensoriese kwaliteit (growwe voorkoms en geroosterde kleur van die droë ontbytgraan, asook geroosterde kleur, mout aroma, geroosterde geur, soet smaak, bitter smaak en mondgevoel van die graan-melk mengsel) op maand 0 en maand 12 van die rakleeftydstudie nie. Die onderskeie ensieme het dus geen betekenisvolle effek op die sensoriese profiel van die KGOG tydens die 12-maande rakleeftydstudie gehad nie. Die mineraalinhoud, dit is die kalsium-, sink- en ysterinhoud van KGOG gefortifiseer met TolP het onderskeidelik met 43.3%, 49.7% en 56.7% toegeneem. Hierdie verhoging van mineraalinhoud het die effektiwiteit van die funksionele ensiem TolP in KGOG effektief geïllustreer, veral gegewe die feit dat hierdie verhoging oor die 12-maande rakleeftyd standhoudend was. Gebasseer op die persentasie aktiwiteit van die funksionele ensiem TolL in die basismateriaal, is gevind dat die ensiemaktiwiteit van TolL ten volle funksioneel was vir nege maande van die totale 12-maande periode. Hierdie resultate sal beslis betekenisvolle toepassing kan vind in produkontwikkeling en bemarking van KGOG. Dit sal ook effektief kan bydra tot die ontwikkeling van gefortifiseerde KGOG vir individue wat laktose-intolerant is of individue wat graag ‘n standhoudende mineraalinhoud-inname wil verseker tydens gereelde inname van KGOG.

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