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    Methods to control the maturation of soft mould ripened cheese : a thesis submitted in partial fulfilment of the requirements of a Master of Technology (in Food Technology), at Massey University.
    (Massey University, 2011) Swan, Shannon
    Soft mould ripened cheeses such as Camembert, typically have a short shelf life in comparison to other cheese varieties, therefore restricting the opportunity to exploit new and developing markets. Preliminary trials were carried out to investigate the freezing point of Camembert cheese and the rate of freezing and thawing that could be achieved using the facilities at Massey University; Albany. Using the results from these trials, a freezing/ thawing protocol and an experimental plan was developed to increase the shelf life by altering the standard storage and maturation profiles of Camembert cheese. Firstly the effect of three storage temperatures and time (for up to four weeks) on the maturation at +4ºC (for eight weeks) of Camembert cheese was investigated. Maturation indicators included: extent of moisture loss of wrapped cheese samples; change in pH of the inside and outside portion of the cheese; change in the release of proteolytic products; change in the viable yeast and mould cells present on the surface of the cheese; and change in texture (uniaxial compression and puncture testing) following storage and throughout maturation. From these results it was found that storing the cheese samples below the freezing point (between -3 and - 3.5±0.1ºC) had a detrimental effect on the maturation of the cheese. The freezing process and time killed the cheese microflora, therefore inhibiting the release of enzymes which promoted the biochemical reactions within the cheese. As a result the cheese did not follow the same maturation trend as the control sample that was matured at only +4ºC for eight weeks. Cheese that was stored at below zero, but above the actual freezing point followed the same maturation trend as the control sample following storage for up to four weeks, therefore showing the most potential in controlling the maturation of the Camembert cheese. The effect of storage at -2ºC on Camembert cheese was then investigated, both throughout the storage of the cheese (for up to six weeks) followed by maturation at +4ºC for eight weeks. Maturation indicators included: change in pH of the inside and outside portion of the cheese; change in the moisture content of the cheese; change in the release of proteolytic products; change in texture (uniaxial compression and puncture testing); and Quantitative Descriptive Analysis using a panel of nine screened and trained panellists. Statistical analysis showed that at the 99% level of confidence, the storage temperature (and time) had no significant effect on the ripening of the cheese throughout maturation at +4ºC of the cheese for all maturation indicators. Therefore, storing Camembert cheese at -2ºC can be used to control the maturation of Camembert cheese, allowing for longer distribution chain delivery times.
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    A study of some aspects of the quality and yield of cheddar cheese made from milk concentrated by ultraflitration : a thesis presented in partial fulfilment of the requirements for the degree of Doctor of Philosophy in the Department of Food Technology at Massey University
    (Massey University, 1986) Iyer, Mani
    Ultrafiltration (UF) is a concentration and separation process which operates at the molecular level. It has been successfully applied to certain soft cheese varieties with the primary advantage of increased yields. When applied to Cheddar, which is a hard variety, problems are encountered. These are lack of flavour and texture development, lack of economically viable yield increase and practical problems in handling of UF curd. An investigation was undertaken to study the application of UF technology to the manufacture of Cheddar cheese. The emphasis was on the biochemical and biophysical problems in UF Cheddar and the possible yield advantages in making the product. Results suggest that UF per se does not contribute to problems in the quality of UF Cheddar. No major problems were encountered in the cheese making process or in final cheese quality when cheese was made from 2:1 UF retentate using conventional method and equipment. There were, however, no yield advantages. When 3:1 and 5:1 retentates were used, some modification in the method of manufacture, particularly in the cutting time and cutting device, was necessary. The quality of cheese obtained from 3 : 1 retentate was found to be inferior while that from 5:1 retentate was comparable with respect to the control cheeses. The biochemical and biophysical problems associated with the quality of UF Cheddar could be overcome to a large extent by adjusting the amount of starter and rennet added on the basis of quantity of milk prior to UF. This yields Cheddar of normal one-day pH but with residual rennet concentration much higher than that in the conventional product. The higher level is probably required to over come the 'dilution' effect of the extra whey proteins present in the UF product. This 'dilution 'effect may be partly due to the difficulty of rennet diffusion in UF Cheddar and partly a result of a decrease in concentration of flavour compounds due to the presence of extra whey proteins. The results show that subs tanti a l savings i n rennet are not possible in cheesemaking from 5:1 UF retentate. The results also suggest that it is possible to make UF Cheddar with a required residual rennet concentration by regulating the amount of rennet added to the retentate and draining the whey at a predetermined pH. The yield advantage in cheesemaking from 5:1 retentate (if UF Cheddar is made to normal MNFS of 53.5%) was limited to 4% largely because only one third of the whey proteins of UF milk was retained in the cheese. Theoretical analysis of mass balance data indicated that this yield advantage could be improved to about 6% by reducing 'fines' losses and to about 8% by decreasing fatlosses as compared with the conventional process. Given the current state of UF cheesemaking technology, it is possible that reductions in losses in conventional cheese-making plants may prove to be a more profitable method of increasing yields of Cheddar cheese than the use of UF cheesemaking methods.
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    Ultra filtration (UF) process development for the production of camembert cheese : a thesis presented in partial fulfilment of the requirements for the degree of Master of Technology in Food Technology at Massey University, Albany, New Zealand.
    (Massey University, 2010) Law, Ming Ho Edwin
    The application of UF technology in cheese production has several potential advantages; product consistency, yield, lower costs and more automation. This study investigated the effects of four processing variables in the manufacture of Camembert cheese using UF and their impact on cheese quality. Using an incomplete block design, sixteen unique treatments were produced with combined processing variables (high-fat or low-fat; brine-salted or retentate-salted; acidified to pH 5.2 or pH 4.9; set in tubular moulds and small moulds). The cheeses were matured for seven weeks at 4±1 ºC and were analysed for total solids, fat, salt, non-protein nitrogen (NPN) and soluble nitrogen (SN) contents during the maturation period (seven weeks). Major defects were evaluated by experienced cheese graders in the fourth week. pH was measured and instrumental analysis was also conducted. Sensory evaluation on consumer acceptance was also conducted in the fourth week. All the cheese samples exhibited similar increases in rind and core pH, NPN/TN and SN/TN ratios, and were generally characterised by thick rind and softness. The lowfat cheese samples had significantly lower NPN/TN ratio and higher overall acceptance in sensory evaluation. The salt content was also significantly higher. The retentate-salted cheese samples had significantly lower NPN/TN ratios and more defects in rind discolouration and deformation, and saltiness. The cheese samples acidified to pH 5.2 had significantly lower NPN/TN ratios and fewer defects in rind discolouration, softness, sourness, and bitterness. The cheese samples made using tube moulds were significantly firmer with fewer defects in rind deformation, core unevenness, and softness. The level of fat and extent of acidification was found to have a profound effect on cheese quality, and cheeses produced with low-fat retentate and/or acidified to pH 5.2 generally had superior shelf-life with lower levels of proteolysis. The preference of the two salting methods may be debatable, but considering labour and time, retentatesalting is preferable. Tube mould generally produced better cheese with fewer defects.