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Item Standardisation of cultured butter processing for smallscale production : a thesis submitted in partial fulfilment of the requirements for the degree of Master of Food Technology at Massey University, Albany, New Zealand(Massey University, 2015) Shi, JiaSummary: Butter is one of the most popular dairy products that have been transformed from a cottage industry to successful large scale productions. In western countries, consumption of butter has slowly overtaken margarine as the most popular spread. Different kinds of butter are now available on the markets, of which sweet cream butter and salted butter constitute significant proportions. The popularity of cultured cream butter is mainly attributed to its unique flavour and nutritional properties. Butter contains large amounts of β-carotene (provitamin A carotenoid) and is characterised by the buttery flavour due to the presence of diacetyl as well as other organic aroma compounds. Although butter has been produced successfully in large scale commercial processing, small scale productions still exists in small communities and for use in specialised products. New Zealand, like in many other western countries, is dominated by small to medium scale food processing enterprises which produce speciality foods for discerning markets. The domestic market in New Zealand enjoys a variety of dairy products which includes cultured butter. Some small food processing enterprises in outlying areas of New Zealand produce their own cultured butter to cater for the local businesses and their inhabitants. Thus, the main objective of this project was to standardise small scale production of cultured butter using kitchen/domestic scale equipment. Fresh cream (40% fat) used to produce cultured butter was fermented by a mixed lactic starter culture (Lactococcus lactis subsp. lactis biovar. diacetylactis and Leuconostoc cremoris) following a modified standard method. The cream was pasteurised at 95°C/5 min, rapidly cooled to 8°C, and then starter culture (2%) was added. The cream was held at 8°C/2 h to initiate the formation of low melting point fat crystals. The temperature of the cream was then increased to 20-21°C, and held at this temperature for further 2 h to melt fat crystals with high melting point and recrystallise the crystals. The temperature was then decreased to 16°C/2 h to form pure fat crystals. This was then followed by slightly decreasing the temperature to 15°C for butter churning in a K5SS KitchenAid Heavy Duty (USA) churning mixer. Buttermilk (100 mL) was collected and stored at 4ºC for analysis and the remained buttermilk in the butter churn was drained. The butter grains were washed with distilled water to remove any residual buttermilk. Final cultured butter (product) was packed in heavy duty aluminium foil and stored at 4ºC for 21 days. Cultured butter was produced on three different occasions commencing in August 2014 (batch 1), September 2014 (batch 2), and October 2014 (batch 3). Various analyses and measurements were conducted during processing and storage to monitor the shelf life stability of the butter. Standard methods were used to measure chemical, physical, consumer sensory acceptance of the products and presence of coliforms were enumerated by Violet Red Bile Agar. Thus, fat content in buttermilk was determined by the Mojonnier test to calculate churning efficiency. Colour was measured by colourimetry, while texture analysis was determined by the TA.XT2 Texture Analyser. Water droplet size of butter was examined by confocal laser scanning microscope after staining with Nile Red and Acridine Orange. The cultured butter samples were also evaluated by consumer sensory panellists using hedonic scaling of six sensory attributes (smoothness, hardness, spreadability, melting rate, buttery flavour, and overall acceptance). Data were plotted on graphs and also analysed by analysis of variance (P<0.05), linear regression and interaction plot. There were significant differences (P<0.05) in moisture content of the three batches of butter which ranged from 13.90 to 19.19%. Although the moisture content of two batches (1 and 3) of butter was slightly higher than the standard (16%), it was within expected range. Manual washing butter grains after churning to remove water droplets may be inefficient to remove water droplets on the surface of butter. Most of the water droplets had a diameter of 5 μm which is desirable to inhibit the growth of spoilage microorganisms. No coliforms were detected in the cultured butter, indicating good hygiene standard during production. There were significant differences (P<0.05) in hardness of the three batches of cultured butter. Batch 2 had higher hardness than the other two batches, probably attributed to its low moisture content. The fat content of cultured butter of the three batches ranged between 75% and 80%, which was slightly lower than the expected 80%. However, the results were reasonable, considering the higher moisture content of the butter. The cultured butter was well accepted by sensory panellists. Linear regression and interaction plot showed that spreadability and buttery flavour had significant effects (P<0.05) on the overall acceptance of the butter. The products were spreadable, presumably due to higher moisture content. The buttery flavour could be attributed to the aroma compounds produced by lactic acid bacteria through citrate metabolism during cream ripening. The dominant hue in the butter was yellowness, which slightly decreased during storage, presumably due to the loss of β-carotene. The pH of butter samples (5.3 to 5.8) during storage was slightly higher than in previous studies (4.7-5.2). The higher pH may be caused by poor acid production of the leuconostoc in the mixed culture. Cultured butter was successfully processed using a kitchen/domestic churning mixer. The churning efficiency of the equipment was lower than the expected range. The butter had good keeping quality and was well accepted by sensory panellists. The quality of the butter during storage was probably attributed to the optimal size of water droplets, which were successfully measured by the confocal laser scanning microscope method modified in this study.Item The role of clover as a factor affecting the summer decline in the vitamin A potency of New Zealand butterfat : being a thesis submitted in partial fulfilment of the requirements for the degree of Master of Agricultural Science of the University of New Zealand, Massey Agricultural College, March 1955(Massey University, 1955) Worker, Neil AdrianPrior to 1913 it was generally assumed that all fats had similar nutritive values and that their only function in the diet was to supply energy. In that year, however, McCollum and Davis (1) of Wisconsin, found in agreement with the earlier observations of Hopkins (2), that rats failed to grow on purified diets in which olive oil, almond oil and lard provided the sole source of fat, whereas normal growth resulted in the presence of milk fat, egg-yolk fat, or cod-liver oil. Almost simultaneously Osborne and Mendel (3), working independently at Yale, observed the growth response or rats on a purified diet of "protein-free milk", protein, and starch was greatly enhanced when fat was supplied as butter-fat (or as whole milk powder) but not as lard. In a subsequent communication (4), Osborne and Mendel confirmed these results and called attention to the prevalence of an inflammation of the eyes of their rats restricted to the lard diet, a condition which they noted to be speedily alleviated by the introduction of butterfat into the diet. Shortly afterwards a similar eye condition, to which they gave the name xerophthalmia, was described by McCollum and Simmonds (5) and likewise shown to be relieved by a supplement of butter or cod-liver oil.Item The rheology of butter : a thesis presented in partial fulfillment of the requirements for the degree of Doctor of Philosophy in food technology at Massey University(Massey University, 1989) Harnett, MichelleA parallel place viscoelastometer was built to perform creep compliance tests on butter and related fats. Creep movement was measured with a linear displacement transducer and recorded by a data logger designed and built for creep compliance experimentation. A temperature of 10°C was maintained by placing the parallel plate viscoelastometer in a refrigerated incubator. A series of preliminary experiments established the creep response was linear and that the direction in which some samples were sheared was critical. The duration of creep compliance testing was also found to affect results. Creep behaviour of butter was assumed to be viscoelastic (based on previous studies) and was modelled with a generalized Kelvin model. Elastic and viscous parameters were fitted to the data by a Marquadt non-linear least squares curve algorithm. Continuous retardation spectra were found by plotting L τ against in time. Data which had been both smoothed and differentiated by the methods of Savitzky and Golay (1964) showed evidence of the existence of three or four main groups of retardation mechanisms. On removal of stress after creep compliance testing a partial recovery of strain was observed, however, samples failed to recover as much as predicted by viscoelastic theory. A second creep/recovery cycle resulted in a responses similar in magnitude to the first recovery. All fat products tested showed the same pattern of response on repeated creep/recovery cycling. An explanation, based on the behavior of polymers, was put forward to explain the observed pattern of response. The crystal network was thought to align in the direction in which stress was applied. The formation of new 'bonds' was then thought to lock the network in its' new position. A number of samples were reworked. The creep curve seen on creep/recovery cycling of reworked samples was similar in shape to that seen for the original samples. However, the curves were three to four times greater than those seen for the original samples. In general, creep response was found to be inversely proportional to hardness. The retardation spectra of reworked samples differed from those seen for the original samples in several ways. The spectra were smoother, the bulk of the spectra had moved to shorter times and they were larger than those seen for the original samples. A survey of seasonal butter samples was also undertaken. Creep compliance parameters were found to correlate well with sectility hardness and solid fat content.Item Efficiency in production of butter : being an investigation into certain factors affecting the economic aspects of technical efficiency of butter factories operating in New Zealand, with special reference to the1949/50 season : a thesis presented to the University of New Zealand in partial fulfilment of the requirements for the degree of Doctor of Philosophy(Massey University, 1956) Vautier, Clyde Percival WilliamNew Zealand's economy is dependent on dairying as a source of national income to a very marked degree, for more than one-third of the country's total export income is derived from this source. Of the total whole milk produced *at the pail* in the 1952-53 season, over 68 per cent was manufactured into creamery butter, yielding 200,000 tons. A revenue in excess of £52,000,000 was derived from this butter. A processing industry of this magnitude and importance merits close attention. Although much time and research have been devoted to technical manufacturing problems, very little analytical work has been conducted in New Zealand on the economic aspect of efficiency in dairy processing industry. Although data are available in the form of reports, compiled statistics and articles, they are descriptive in character, or mere compilations. As such they fail in the important task of analysis of the conditions they describe. It seems strange that in a country like New Zealand where the standard of scientific reasearch is so high and where the dairy industry contributes so much to the national economy, that so little is known of the economic aspects of the dairy industry. Apart from TASKER's two papers TASKER, J.P. (1938;: The Cost and Capitalization of North Auckland creameries during 1935-36. The Accountants' J. (August) - New Zealand Creamery Costs and Pay-outs for the 1937-38 Season. N.Z.Jnl. of Science and Technology, Vol. 26. Np.4 (Sec. A), PP. 204-213, 1944. the amount of analytical research is almost nil. The valuable information compiled by the New Zealand Dairy Board is largely descriptive and statistical and does not throw light upon the problems as investigated by research workers in this field overseas. See Appendix A: "Related Studies".