Sample Solution

set at 0.05. Duncan`s HST test at 5% significance level was used as the multiple comparison test on all main effect means.

RESULTS AND DISCUSSION

Chemical Analysis: processed cheese had protein content of 12%, fat content of 23% and moisture content of 56.67%. Samples did not show any significant differences in, protein, fat and moisture and these properties did not change significantly (P > 0.05) during storage (results are not shown). This could be because of low levels of powders added to the samples and did not make significant difference in these properties. In the case of pH, there were significant difference between control and fortified cheeses. Bin Shan et al.6 reported that herbal extracts with high phenolic contents in cheese samples, prevented the increasing of pH, during storage. Results showed that pH has been decreased by increasing asparagus and tomato level in cheese formulation and it was decreased during storage. However, pH changes in cheeses fortified with tomato powder were as control sample during storage (Tables 1 and 2).

Lycopene contents of samples increased with the increasing of tomato powder. Lycopene content decreased during storage which was severe at the beginning of storage, then followed by slow lycopene degradation (Table 3). Lycopene is a carotenoid found in fruits and vegetables which is responsible for the redness of tomato and tomato based products. Lycopene can act as an antioxidant and has many positive effects on prevention of many diseases25. Therefore, cheeses fortified with tomato powders can be as functional and healthier food products in our daily diet.
Lycopene has been added as a functional ingredient in several kinds of cheeses such as Queso Blanco cheese supplemented with powdered microcapsules of tomato extracts26 and other foods such as extruded snacks fortified with lycopene27.
Generally, lycopene level of fortified cheese were decreased by 63% during 90 days of storage (Table 3). It shows that lycopene is preserved in cheese during storage and consumers can get health benefits from their consumption.

Total phenolic compound of tomato is 2.68 mg/ g of DW25 and total phenolics of asparagus is 5 mg catechin equivalent/ g DW28. Also, medium chain peptides produced by rennet, may act as phenolic compound. WSPC of fortified cheeses were higher than those of control at first days of storage. However, WSPC of fortified cheeses decreased during storage. On the other hand, WSPC of control sample did not change significantly (P > 0.05) during storage (Tables 4 and 5). Decrease of WSPC of fortified cheeses during storage may be due to the absorption of phenolic compounds of tomato and asparagus by some peptides (produced by rennet and starter during storage) which neutralizes and deactivates the phenolic compounds presented in cheese8. Fadavi and Beglaryan8, reported that peppermint showed a lower WSPC in UF feta cheese than expected, and rennet had a positive effect on WSPC in UF feta cheese. It has been explained that, this paradox may be due to the absorption of phenolic compounds of peppermint by some peptides. The retention of phenolic compounds in cheese is related to the interactions between p