Ters Ozmoz Teknolojisinin Beyaz Peynir Üretiminde Kullanımı

Abstract

Due to technological developments and economic reasons, the use of membrane filtration systems in the dairy industry has been increasing in recent years. Especially in cheese production, microfiltration and ultrafiltration are widely used systems but reverse osmosis applications are limited. However, it is seen that research on this subject is gaining interest. The aim of this study was to investigate the potential of using milk concentrated by reverse osmosis technology in white brined cheese production. For this purpose, firstly, compositional, color measurement, viscosity, rennet coagulation time, particle size and zeta potential analyses were performed on raw milk (1.0X) and raw milk concentrated by reverse osmosis (1.5X, 2.0X). According to the results, white brined cheese production trials made by reverse osmosis concentrated milk and the necessary modifications in the traditional white brined cheese method were determined and production recipes were prepared for actual production. In the second part of the study, white brined cheese was produced using these milks and microbiological, chemical/biochemical, microstructural, textural and sensory properties of the cheeses were analyzed during the ripening period (7th, 30th, 60th and 90th day). In addition, the yield calculation of the cheeses was performed.

As expected, the concentration of cheese milk by reverse osmosis significantly affected the cheese composition, viscosity and color values of the milk samples. The pH values in raw milk decreased with increasing concentration. While pH was 6.72 in 1.0X raw milk, it was 6.55 and 6.50 in 1.5X and 2.0X raw milk, respectively. Although the starter activity was negatively affected in 2.0X milk, it was determined that this negativity could be overcome by selecting mixed starter cultures and increasing the incubation time. There was a significant increase in the rennet clotting time with increasing concentration.

The moisture-adjusted yield values of cheese samples were higher in the cheeses produced by 1.5X and 2.0X milk. There was no significant difference between the results of lactococci and lactobacilli counts in the cheeses. The compositional results showed that lactose value was found to be significantly higher in 2.0X cheeses (4.30% in dry matter). In accordance with the increase in the concentration of the milk, an increase was detected in the dry matter ratios of the cheeses produced. Microstructures of cheese samples were analyzed, scanning electron microscopy (SEM) and confocal laser scanning microscopy (CLSM) images revealed a firmer structure with an improved protein network in the cheeses produced with concentrated milk. Proteolysis was more advanced level in the control group cheeses (1.0X). According to SDS electrophoretograms, the ratio of serum protein (α-lactalbumin and β-lactoglobulin) retained in the cheese structure was lower in 1.5X and 2.0X cheeses compared to control cheese. According to principal component analysis (PCA) applied to the RP-HPLC peptide profile, the cheeses produced with 2.0X concentrated milk were significantly different from the others. In addition, the soluble serum protein (α-lactalbumin and β-lactoglobulin) ratios were significantly higher in 1.5X and 2.0X cheeses.

While the total free fatty acid levels of the cheeses produced from 1.0X and 1.5X retentates were close to each other, the total free fatty acid content of the cheeses produced from 2.0X retentate was found higher. PCA was applied to the volatile component analysis data performed by GC-MS-SPME method and the components causing the differentiation were determined. According to PCA data, RO concentration and ripening time significantly affect the volatile component profile of cheeses. Hardness values were higher in 1.5X and 2.0X cheeses and these results were supported by sensory evaluation. In terms of sensory evaluation, 1.5X cheeses received higher scores. In addition, bitterness defect was detected in 1.0X cheeses, and mild sweetness was detected in 2.0X cheeses. As a result; it was observed that products with similar properties to brined white cheese can be obtained by using RO retentates. Considering the economic advantages and operational efficiency it can provide, it is foreseen that RO technology can be applied in white cheese production.