Phenolic Content and Antioxidant Activity of Extracts of 12 Melon (Cucumis melo) Peel Powders Prepared from Commercial Melons

Abstract

Melons are a diverse group of fresh, dessert fruits that includes orange flesh cantaloupe, green flesh honeydew, and mixed hybrid melons. As part of an effort to discover potential health benefits of fruit and vegetable peels that are considered to be byproducts of food processing, we determined the total phenolic content and antioxidative activities of methanolic extracts of the powdered peels of the following commercial melon (Cucumis melo) varieties sold at retail markets in California that were imported from Mexico and Honduras: nonorganic Canary, Charentias, Hani Gold, Vine ripened, and Santa Claus; and organic Ambrosia, Cantaloupe, Galia, Goddess, Ham, Honeydew, and Tuscan. The total phenolic content (in mg gallic acid equivalents/g extract) ranged from 0.69 (Tuscan) to 2.96 (Galia) or 4.3‐fold variation from lowest to highest value. The antioxidative activity (in mg ascorbic acid equivalents/mL extract) ranged from 0.13 (organic Tuscan) to 0.26 (organic Galia). Similar results were observed using the ABTS antioxidative assay. The content of the phenolic and flavonoid compounds 3‐hydroxybenzoic acid, chlorogenic acid, neochlorogenic acid, isovanillic acid, apigenin‐7‐α‐glucoside, luteolin‐7‐o‐glucoside, and quercetin‐3‐galactoside in three melon flesh samples (nonorganic and organic Galia from Honduras and organic Galia from Mexico and two peel samples (Mexican organic peel and flesh) were analyzed using HPLC. The results suggest that the peel from the Honduran Galia melon with the highest antioxidative activity merits further study to investigate potential health properties. Potential nutritional and health benefits of melon peels, Seeds, and their bioactive compounds are discussed. Practical Application The peel from the Honduran Galia melon variety merits further study for potential health benefits, including antioxidative, anticholesterol, and antidiabetic activities, and stimulation of thyroid function, as reported for peels from other melon varieties, as well as antibiotic activities against pathogenic bacteria, protozoa, and viruses.

Acrylamide Content of Experimental Flatbreads Prepared from Potato, Quinoa, and Wheat Flours with Added Fruit and Vegetable Peels and Mushroom Powders

“…Table 6 shows that adding 5 or 10% Galia melon peels to wheat flour did not affect the acrylamide levels of the baked flatbreads. In a previous study, we have reported that the melon peel used here contained phenolic compounds and flavonoids, and showed the highest antioxidative activity of 12 evaluated melon peel powders [16].…”

“…As part of this effort, we have shown that (a) the dietary supplementation of potato peel powders reduced weight gain in mice on a high-fat diet [12]; (b) potato peel powders inhibited the growth of pathogenic trichomonads (protozoa) that cause sexually transmitted diseases in humans and cattle [13]; (c) apple, orange, and potato peel powders inhibited the outgrowth of pathogenic Bacillus cereus bacteria from spores in cooked rice [14]; and (d) a rice hull smoke extract reduced weight gain in mice on a high-fat diet [15]. We also recently determined the content of phenolic and flavonoid compounds and antioxidative activities of 12 melon peel powders [16].…”

Multivariate Analysis of Amino Acids and Health Beneficial Properties of Cantaloupe Varieties Grown in Six Locations in the United States

“…The variation in the total phenolics content may be due to cantaloupe cultivars and growing locations. The prominent phenolic compounds reported in melon have been isovanillic acid, coumaric acid-hexoside, hydroxyl-benzoic acid hexoside, chlorogenic acid, apigenin-7-α-glucoside, ferulic acid, and luteolin-7-O-glucoside [ 36 , 44 ]. The antidiabetic potential of cantaloupe was evaluated by determining their capacity to inhibit the α-amylase activity that is responsible for breakdown of polysaccharides to monosaccharides.…”

“…Similarly, in tomato plants, GABA enhanced the level of gallic and coumaric acids under salinity conditions [ 80 ]. Our results show that variety F-39 had high GABA ( Figure 4 ) and total phenolics content ( Figure 8 A) in NC and IN; this may be due to accumulation of phenolic acids such as ferulic and p-coumaric acids, which are known as prominent phenolic compounds in cantaloupe [ 36 , 44 ]. Similarly, the TT-DV variety also had high levels of GABA and total phenolics content in NC, IN, and AZ.…”

“…Yang et al found that low light intensity significantly influenced the sucrose and galactosyl-sucrose oligosaccharide metabolism in both melon fruits and leaves [ 40 ]. In melons, the levels of amino acids and antioxidants vary with growing conditions and genotypes [ 41 , 42 , 43 , 44 ]. Therefore, qualitative and quantitative analyses of fruits grown in different locations are essential for quality control and the production of improved varieties.…”