Abstract 1029 Studies on honey samples from the southwestern region of Saudi Arabia: Their antioxidant activities related to their content of essential amino acids and proteins

Objectives: This study was designed to explore the effect of the geographical and floral origins on some honey quality parameters (moisture, pH and acidity, Electrical conductivity and total sugars), honey total protein concentration, honey ultra-short peptides content and the antioxidant activity of honey. Methods: The floral origin of the honey samples was determined microscopically and the quality parameters of the honey were measured according to the methods of the international honey commission. The total protein concentration was assessed following the spectrophotometric method of Bradford. The LC/MS technique was used to detect the short peptides in the honey samples. The 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical scavenging assay and the ferric reducing antioxidant power (FRAP) assay were used to determine the antioxidant activity of the honey samples. The obtained data were statistically analyzed using the statistical package for social sciences (SPSS). Results: The microscopic analysis showed that the samples were Acacia, Ziziphus and polyfloral honey samples. All the quality parameters were within the ranges of the Codex and Saudi Food and Drug Authority (SFDA) standards as follows: moisture (˂ 20%), pH (3.6- 5.15), Acidity (10.0- 50.0 meq of NaOH/Kg), and EC (35- 1290 μS/cm). The geographical origin had insignificant effect on the studied honey quality parameters (p- value ≥ 0.089). The floral origin in Jazan region had significant effects on some of the studied quality parameters (pH, moisture and total sugars). The range of the protein concentration in the honey samples was (447.2- 1260.8 μg/g). The total protein concentration of the honey samples was significantly affected by the floral origin in Asir region and the geographical origin significantly. affected the total protein concentration of the polyfloral honey (p- value≤ 0.011). The range of the ferric reducing antioxidant power of the honey samples was (17.65- 29.61 mg of Fe+2/g). The floral origin of the honey samples from Asir region significantly affected the antioxidant reducing power of the honey samples (p- value= 0.008). The ferric reducing antioxidant power of the polyfloral honey of Asir region was significantly increased compared to that of the polyfloral honey from Jazan region (p- value= 0.01). Thirty five ultra-short peptides were found in the honey samples of Jazan region while Asir region contained eight ultra-short peptides. The polyfloral honey samples were the richest honeys with ultrashort peptides followed by Acacia honey. Conclusions: The geographical region of the honey samples significantly affected the total protein concentration, the FRAP and DPPH activities and the number of ultra-short peptides. The floral origin of the honey samples had significant effect on pH, moisture, total sugars, total proteins and FRAP activity.