Browsing by Author "Parker, Michael Edward"
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- ItemDesign of a process for the manufacture of beef stock : a thesis presented in partial fulfillment of the requirements for the degree of Doctor of Philosophy in Food Technolgy at Massey University, Manawatu Campus, Palmerston North, New Zealand(Massey University, 2014) Parker, Michael EdwardThis work deals with the development of a process for the production of commercial stock from beef bones using a formal food process engineering analysis instead of random experimental trials of potential processes. The major difference between a food and a traditional chemical process engineering analysis is the inclusion of the food functional, textural and/or sensory properties besides the yield and efficiency in the optimal design. These properties often interact with the process and equipment design. The bones were extracted with hot water and the kinetics of extraction determined by following the changes in soluble solids over time. Extraction curves measured at several temperatures between 80 and 120°C could be modelled using first order rise to an equilibrium concentration and the effect of extraction temperature could be measured using the Arrhenius law. Despite the presence of gelatine in the aqueous stock extracts, which is known to produce strongly time-dependent non-Newtonian solutions, they were found to be Newtonian for temperatures above 20°C. Thus the Newtonian viscosity of the aqueous extracts was measured as an indicator of stock texture. Textural changes due to exposure to high temperatures over time were determined for temperatures between 60 and 120°C and found to follow first order kinetics. The effect of temperature followed the Arrhenius law. An equilibrium curve for bone extraction in hot water at 120°C and a maximum yield of extractable solids non-fat were also determined. A mathematical model was constructed on an Excel platform using the kinetics of extraction and textural changes as well as the equilibrium data. It is based on a novel method of analysis of multi-stage solid-liquid extraction called “stage wise iterative analysis” and gave a profile of soluble solids concentration and viscosity during the extraction and concentration phases of the manufacturing process that fell within less than 10% of experimental measurements. Simulations showed that soluble solids concentration, viscosity, yield and processing time all impacted on the optimum design. These analyses highlighted the significant importance of reducing the run time from the current 6 days to 5 hours as it has the potential to increase the production rate and therefore revenue ten-fold with a minimum change in equipment. The higher extraction rate can be achieved by increasing the extraction temperature from the current 92°C to 120°C. While the rate of losses of viscosity and therefore texture is increased with the higher processtemperature, the model showed that the great reduction in processing time more than compensates for the temperature effect and the viscosity of the final stock extract is greater than that found in the current industrial operation. It was also found that the yield of extracts from the bones could be improved significantly by conducting a multi-stage semi-counter current extraction instead of a single stage extraction for the same overall extraction time. Preliminary considerations were given to the use of secondary product streams, high quality tallow and calcium phosphate to improve further the financial returns of the process. Finally a process modification was considered to improve the consistency of the flavour properties of the stock. It was proposed that separating the meat from the bones and roasting it in a smaller oven to allow quick and separate extraction of the flavour components found in the commercial stock. These can be added back to the bone extracts in standardised quantities to produce a product of consistent flavour.
- ItemThe development of extruded meat alternatives using Maillard-reacted beef bone hydrolysate and plant proteins : a thesis presented in partial fulfilment of the requirements for the degree of Doctor of Philosophy in Food Technology at Massey University, Palmerston North, New Zealand(Massey University, 2020) Chiang, Jie HongThis research thesis aimed to process beef bone extract into a flavoursome protein ingredient to be added to extruded meat analogues to form meat alternatives and study their impact on the structural, textural, and sensory properties of meat alternatives. The thesis consists of three main parts. In the first part, two methods namely enzymatic hydrolysis and Maillard reaction (MR) treatments were evaluated for their suitability of modifying the flavour character of beef bone extract to become flavoursome protein ingredients. The second part studied the effects of soy protein concentrate (SPC) to wheat gluten (WG) ratio as a way of improving the structural and textural properties of current extruded meat analogues. The third part studied the effects of flavoursome protein ingredient (i.e. Maillard-reacted beef bone hydrolysate) with plant proteins on extruded meat alternatives. It also investigated the effects of moisture contents on extruded meat alternatives and their application in sausages. To begin, an experimental study on the effects of enzymatic hydrolysis treatments (i.e. single, simultaneous and sequential) on the physicochemical properties of beef bone extract using Protamex®, bromelain, and Flavourzyme® was conducted. Next, the changes in the physicochemical properties and volatile compounds of beef bone hydrolysates during heat treatment as a result of the MR were investigated. Beef bone hydrolysates were combined with ribose in aqueous solutions and heated at 113°C to produce Maillard reaction products (MRPs). Results showed that Flavourzyme® was the most effective in increasing the proportion of low Mw peptides, reducing viscosity and enhancing the flavour intensity of beef bone extract. Concurrently, the effects of SPC to WG ratio at a constant mass of SPC and WG on the physicochemical properties of extruded meat analogues were studied. Meat analogues containing 30%WG showed the highest degree of texturisation, fibrous structure, hardness and chewiness using instrumental and sensory analysis. For the third part of this research thesis, the effects of flavoursome protein ingredient (i.e. Flavourzyme®-MRP) at different concentrations (0, 10, 20, 30 and 40% wet weight) with plant proteins on extruded meat alternatives were investigated. Meat alternatives containing 20%MRP obtained the highest sensory scores for appearance, meaty aroma, meaty taste, and overall acceptability. Results showed that the addition of MRP with soy protein concentrate and wheat gluten to produce meat alternatives changed the textural, structural, and sensory properties significantly. The effects of moisture content (MC) on the physicochemical properties of extruded meat alternatives made from Flavourzyme®-MRP and plant proteins were studied. Samples were extruded at different dry feed rate of 1.8, 2.2, 2.6 and 3.0 kg/h to obtain MC of 60%MC, 56%MC, 52%MC and 49%MC, respectively. Meat alternatives at 49%MC were the closest in terms of both textural and microstructural properties to reference sample, boiled chicken breast. Results showed that the change in MC as a process parameter played an important role in the formation of fibrous structure in extruded meat alternatives. Lastly, the physicochemical properties of sausages made from extruded meat alternatives at different MC were conducted. Five sausages made from meat alternatives (S49%MC, S52%MC, S56%MC and S60%MC) and chicken breast (SCB) as a reference sample were prepared. Results showed that S49%MC had the highest sensory scores among all sausages made from meat alternatives. However, SCB obtained the highest sensory scores for all attributes except for appearance among all sausages at a 95% confidence level. Overall, the present work demonstrated that a flavoursome protein ingredient (i.e. Flavourzyme®-MRP) from low-value meat by-product (i.e. beef bone extract) can be successfully incorporated into extruded meat analogues to form meat alternatives with high aroma and taste quality while maintaining fibrous structure. However, further work needs to be done to improve the textural and sensory properties of sausages made from extruded meat alternatives.