# Evaluation of a New Bulk Packaging Container for the Ripening of Feta Cheese
## 3 Results and Discussion  
### Physico-Chemical Parameters of Feta Cheeses  
Changes in the physico-chemical parameter values of cheeses as a function of the packaging material and ripening time are shown in Figure 1. pH (Figure 1a) decreased (\(p\) < 0.05) with ripening time, ranging between 4.85 (day 1) and 4.34 (day 100), with the packaging material having no effect (\(p\) > 0.05) for a given sampling day. During ripening, lactose is broken down into lactic acid, resulting in a decreased pH. Acid production is a highly important criterion in the manufacture of cheeses ripened in brine due to the inhibitory effect of lactic acid on the growth of undesirable microorganisms and curd stability during brining [12]. Regarding moisture (Figure 1b), cheeses ripened in the wooden barrel and stainless-steel tank recorded lower (\(p\) < 0.05) moisture content during the later stages of storage compared to the samples in the tin can. This may be explainedby the fact that, of the three packaging materials, only the tin can provided a hermetically sealed environment, resulting in cheeses with a higher moisture content. Moisture content decreased (\(p<0.05\)) with ripening time, ranging between 58.2% (day 1) and 52.1 (day 100). This is explained by the fact that, during ripening, moisture is expelled out of the cheese while salt diffuses into the cheese mass [3]. According to [PERSON] [13], the loss of moisture during cheese ripening is twice as high as the rate of NaCl entering the cheese mass, in proportion to their molecular sizes. Regarding fat (Figure 1c), cheeses ripened in the wooden barrel and stainless-steel tank recorded higher (\(p<0.05\)) levels of fat content compared to the sample in the tin can, a fact that can be justified by the lower moisture content of cheeses packaged in wooden barrels and stainless-steel tanks. As moisture dropped during ripening, the fat content increased (\(p<0.05\)), ranging between 21.0% (day 1) and 25.5% (day 100). A similar trend regarding the effect of the packaging material and ripening time was shown for the protein content (Figure 1d) as for fat. Protein content ranged between 16.24% (day 1) and 19.54% (day 100). Regarding lactose (Figure 1e), no statistically significant effect (\(p>0.05\)) of the packaging material was recorded for a given sampling day. This finding is in agreement with pH values recorded in the study. Lactose decreased (\(p<0.05\)) during ripening, ranging between 0.83% (day 1) and 0.20% (day 100) as lactose was converted to lactic acid. Finally, regarding salt content (Figure 1f) cheeses ripened in the wooden barrel and the tin can recorded a higher (\(p<0.05\)) salt content compared to the sample in the stainless-steel tank, which is probably related to the different ratios of (brine volume)/(cheese weight) in the three packaging materials used, and possibly to the method of salting (dry salting vs. brine). Salt content increased (\(p<0.05\)) during ripening, ranging between 1.05% (day 1) and 2.37% (day 100), as salt slowly diffuses into the cheese mass with time. The extent of proteolysis, the major biochemical event that takes place during cheese ripening, was monitored through the determination of the water-soluble nitrogen (WSN), the nitrogen soluble in 12% trichloroacetic acid (TCA-SN) and the nitrogen soluble in 5% phosphotungstic acid (PTA-SN) (Figure 2). The % TN (Figure 2a) was affected (\(p<0.05\)) by both the packaging material and the ripening time. Cheeses ripened in the wooden barrel and stainless-steel tank recorded a somewhat higher (\(p<0.05\)) % TN beginning with day 40 of storage, compared to the sample in the tin can, a finding that may be explained by the lower moisture content of cheeses packaged in the wooden barrel and the stainless-steel tank during the ripening process. As the moisture level dropped in the cheeses during ripening, the % TN increased (\(p<0.05\)) from 2.54% (day 1) to 3.00% (day 100). This trend is in agreement with the results for changes in protein content.