# Evaluation of a New Bulk Packaging Container for the Ripening of Feta Cheese
## 3 Results and Discussion
### Physico-Chemical Parameters of Feta Cheeses
The % WSN (Figure 2b) was also affected (\(p<0.05\)) by both the packaging material and the ripening time. Cheeses ripened in wooden barrels recorded the highest (\(p<0.05\)) % WSN content beginning with day 40 of storage, compared to samples ripened in stainless-steel tanks and tin can. This may be related to the cheeses packaged in wooden barrels having the lowest moisture content compared to the other two packaging materials, resulting in the highest protein content and, logically, in the highest % WSN of cheeses. Regarding the effect of time, as the ripening process proceeded, the % WSN increased (\(p<0.05\)) with time due to the gradual breakdown of proteins, ranging from 9.70% (day 1) to 11.51% (day 100). The WSN fraction contains whey proteins, protease-peptone (soluble proteins, peptides, amino acids, amines, urea, ammonia), and low-molecular-weight peptides (<15,000 Dalton molecular mass) derived from casein hydrolysis. According to [PERSON] and [PERSON] [14], the soluble nitrogen compounds are mainly produced by the action of the coagulant. The greatest part of the water-soluble nitrogen consists of nitrogen that is soluble in 12% trichloroacetic acid (TCA), corresponding to medium and small-sized (600-15.000 15,000 Dalton molecular mass) peptides with 2-22 amino acids [3]. According to [PERSON] et al. [15], rennet, bacterial proteinases, and peptidases are responsible for the formation of 12% trichloroacetic acid-soluble nitrogen (TCA-SN). The % TCA (Figure 2c) was affected (\(p<0.05\)) by both the packaging material and the ripening time. Cheeses ripened in wooden barrels recorded the highest (\(p<0.05\)) % TCA content compared to samples ripened in stainless-steel tanksand tin cans. The explanation for this finding is the same as that for % WSN. Regarding the effect of time, as the ripening process proceeded, the % TCA increased (\(p<0.05\)) due to the gradual breakdown of proteins, ranging from 6.21% (day 1) to 9.68% (day 100). Finally, the % PTA followed the same trend as % WSN and % TCA, ranging from 0.95% (day 1) to 1.97% (day 100). The % PTA (Figure 2d) is made up of amino acids and peptides with molecular weights of less than 600 Dalton, which are soluble. The % PTA value is strongly related to the age and flavor intensity of the cheese [3]. Figure 1: Main effects plots for the physicochemical parameters of (**a**) pH, (**b**) % moisture, (**c**) % fat, (**d**)% protein, (**e**) % lactose, and (**f**) % salt of feta cheese as a function of the packaging material and ripening time. The only relevant study in the literature, that of [PERSON] et al. [5], investigated the effect of packaging materials (wooden barrels and tin cans) on the physico-chemical parameters of Feta cheese prepared from 100% ewe milk using a combination of (i) a conventional starter culture (_Streptococcus salivarius_ subsp. _Thermophilus_ and _Latchobacillus L. delbrueckii_ subsp. _bulgaricus_) and (ii) artisanal kid and lamb renet. The above authors reported a lower moisture content and a higher fat content for Feta cheese packaged in wooden barrels compared to that packaged in tin cans, in agreement with results of the present study. However, Feta in barrels had a lower salt content than Feta cheeses stored in tin and a similar protein content after 60 days of storage (the minimum ripening period according to the Greek Codex Alimentarius Athens, Greece [16]). They also reported that packaging material had no effect on proteolysis indices. All physico-chemical parameter values reported in the present study are in general agreement with those of [PERSON] et al. [17] and [PERSON] et al. [18] for Feta cheese; [PERSON] et al. [19] for brined cow cheeses; [PERSON] et al. [9] for full- and reduced-fat brined goat cheese; and [PERSON] et al. [20] for brined ewe cheeses. Differences among the studies, especially those related to proteolysis fractions, may be related to the addition of different renet, the use of different types of milk, and minor differences in the cheese-making process.