The current investigation carried out on blends of two species from cactus pear (CP) juices with guava juice to evaluate the changes in physicochemical properties, ascorbic acid, phytochemicals, antiradical activity as well as volatile compounds. The blends of purple CP showed a significant increase in pH, TSS and ratio of TSS/TA values compared to blends of green CP with guava juice. An opposite trend had occurred in determination of titratable acidity. Ascorbic acid concentration in blends ranged from 42.45 to 59.43 mg/100 mL in T1 and T3 respectively. The blends showed a remarkable increase in total phenolic content with the increase of cactus pear in blends in formula to reach the maximum level at T1 and T3. Against reducing power, the antiradical activity was generally higher than that of DPPH by factor about 1.3 at T1 and 1.4 at T6. The radical scavenging activities of studied blends were in the range of 8.37 -13.46 μmol TE/100 mL in T6 and T1 respectively when the determination carried out using DPPH assay. The highest score of panellists recorded for the T3 [(3) purple pear: (1) guava juice). Therefore, this blending ratio subjected to GC-MS analysis. Thirty volatile compounds were identified; the major alcohols in T3 were 1hexanol and linalool which represent 12.35% and 7.23% respectively.

Snacks are routine light-food, consumed between meals by children or adults. It is important to enhance their safety properties and shelf life, without losing the acceptability. This investigation aimed to achieve that, using a modified rice straw (MRS), stabilized rice bran (SRB), and barley bran (BB) to substitute wheat flour (WF) in functional snacks. The microbiological-safety impact of substituted materials and their aflatoxins-prevention were evaluated. Antifungal properties against toxigenic fungi were arranged to descend as MRS>SRB> BB. Organoleptic characteristics were significantly decreased at a higher SRB and MRS substitution-values. The best snacks-acceptability was recorded for a 10% substitution ratio. Therefore, volatiles content was identified using GC-MS analysis at 10 % substituted snack. The most predominant volatiles were 2,3-butanedione, 3-methyl butanal, and 2-methyl butanal by concentrations of 26.84%, 11.48%, and 7.94%, respectively in control snacks. These volatiles activities are explaining degradation of aflatoxin-secretion.

Snacks fortified with Jameed are new candidates for use as protein supplements. The effect of the fortification of snacks with natural sources of protein such as Jameed at levels of 5%,10%, 15% and 20%, respectively on the physicochemical properties, antioxidant activity, nutritional, sensory properties and volatile compounds were determined compared to control snacks. The high levels of fortification characterized with high protein, fat, fiber and ash content. However, sensory data showed that snacks fortified with 5% Jameed recorded the highest score in sensory attributes. The results showed that the highest total phenolic content (1.29 mg/g) was found at 20% level compared to all treatments and control. The data exhibited a significant increase (P≤0.05) in antioxidant activity with the increase fortification level of snacks with Jameed. Thirty-three volatile compounds were identified in control as well as fortified snacks with Jameed at levels of 5 and 10% using GC-MS. The volatile compounds had arranged as following; 9 (alcohols); 8 (aldehyes); 5 (ketones); 3 (esters); 3 (furans); 3 (acids) and 2 (terpenes). The data indicated that the fortification with 5% Jameed recorded the highest sensory attributes may be related to the elevation of concentrations of aldehydes especially 2-methyl propanal, 2-methyl butanal and 3-methyl butanal as characteristic volatile in snacks.