Records of Agricultural and Food Chemistry Articles

Honey is well known for its nutritional and therapeutic potential since ancient time. The current study was designed to investigate the chemical composition, antioxidant and enzyme inhibitory activities of nine Saudi honey types. Three extracts, ethanol, methanol and aqueous, were prepared from each type. Results of fructose, glucose, sucrose and 5-hydroxymethylfurfural contents in the tested Saudi honey types indicated their good quality with the honeyofSider Bisha and Sider Albaha occupied the highest position. Polar extracts of honey recorded the highest TPC and TFCvalues and the best values were recorded from the aqueous extract of Sider Bisha (197.67 mg GAE/100 g) and Talh Hail (67.45 mg RE/100 g) respectively. All honey extracts showed significant antioxidant activity and the MeOH extract of Sider Bisha displayed the highest anti-ABTS (809.42 mg TE/g) and chelating (98.71 mg EDTAE/g) properties and that of Sumra Bisha recorded the best anti-DPPH activity (30.67 mg TE/g). The aqueous extract of the latter and that of Talh Hail revealed the best Fe++ (248.41 mg TE/g) and Cu++ (256.72 mg TE/g) reducing capacity. All honey types exerted remarkable enzyme inhibitory activity; all extracts of Sumra Bisha, EtOH and aqueous extracts of Sider BishaandSiderTehamhandMajraaswellasaqueousextractofTalhTehamhandMeOHextractofTalhHailexerted remarkable anti-acetylcholinesterase effect (9.64–10.23 mg GALAE/g; p ≥ 0.05) while aqueous extract of Sumra Bisha andSiderAlbahaexhibitedthehighestanti-butyrylcholinesteraseeffect(16.46and15.13mgGALAE/g;p≥0.05).MeOH extract of Qatada honey recorded the highest anti-Tyr effect (260.95 mg KAE/g). These findings indicated that the nine Saudi honey types are of good quality, high bioactive molecules and could play a significant role in oxidative stress.

Kunun zaki is a traditional cereal-based fermented beverage widely consumed in West Africa; however, its nutritional quality and microbiological stability are often limited due to spontaneous fermentation. This study investigated the effects of controlled fermentation using defined lactic acid bacteria (LAB; Lactobacillus acidophilus and Lactobacillus plantarum) combined with graded tigernut supplementation (10–40%) on the amino acid composition and microbial quality of sorghum-based kunun zaki beverage. Five formulations were produced: a spontaneously fermented 100% sorghum (control) and four LAB-inoculated sorghum-tigernut blends. Amino acid profiles were determined and microbiological quality was assessed during 72 h of storage. Controlled LAB fermentation significantly improved the essential amino acid profile of kunun zaki, with notable increases in lysine, isoleucine, and valine in tigernut-enriched formulations (p < 0.05), indicating enhanced protein quality. Tigernut supplementation contributed to compositional complementation, further increasing essential amino acid density without disrupting the EAA/NEAA balance. LAB-fermented samples exhibited sustained LAB dominance (>5.5 log10 CFU/mL), absence or minimal detection of coliforms and fungi and improved microbial stability compared with the control during storage. Among the formulations, the 70% sorghum: 30% tigernut blend demonstrated the most balanced nutritional and microbiological profile. These findings demonstrate that integration of defined LAB starter cultures with optimized tigernut inclusion represents an effective biotechnology strategy for enhancing the nutritional value, microbial safety and storage stability of kunun zaki, thereby supporting its development as an improved functional beverage with commercialization potential.

Diodia sarmentosa, also known as tropical buttonweed, is used traditionally as a culinary ingredient and medicinal plant. This work focused on the determination of optimum conditions for extraction with high yields and evaluation of antityrosinase and antiradical properties of D. sarmentosa. Optimization of extraction was performed using response surface methodology (RSM) based on a central composite design. Three variables including mass of plant material, extraction time and ethanol proportion were used for the extraction under ultrasound-assisted conditions and the major compound was isolated and characterized using 1H NMR and 13C NMR as oleanolic acid (OA). The yield of extraction was significantly influenced by mass of plant material, ethanol ratio and extraction time. Highest extraction yield of 40.42% was obtained from 850 g of plant material for an extraction time of 20 mins with ethanol proportion of 80% in water. The extracts resulting from experiments with best yields 40.42 % and 37.02% were exhibited good antiradical property with IC50 values of 08.1±0.5 µg/mL and 08.7±0.4 µg/mL in the DPPH· assay. The extract with a yield of 28.47%, obtained from 850 g of plant material, after 8 mins of extraction time in 80% ethanol proportion had highest tyrosinase inhibition with IC50 value of 52.7±1.4 µg/mL. These suggest that mass of plant material and ethanol proportion are important for tyrosinase inhibition and antiradical activities. Oleanolic acid showed very weak antiradical activity with moderate tyrosinase inhibition. Molecular docking showed low binding affinity with the binding sites of tyrosinase, mostly through Van der Waals interactions with a binding energy of -6.3 kcal/mol. However, the overall results indicate potential cosmetic and food applications of D. sarmentosa.