Biotechnological production of high-value products from wastes of mango processing industry-phase 2

Enzymatic extraction of essential oil from fresh mango peel recorded an oil yield of 0.15 to 0.46% (w/w) on fresh basis and 0.87 to 2.08% (w/w) on dry basis which was within the reported yield in other essential oils. The oil can be used as fragrance oil in cosmetic and perfumery industries. Extraction of phenolics from fresh peel by enzymatic process was also conducted. The highest polyphenol yield of 0.87% (w/w) was obtained at pectinase level of 10 PTE units/g fresh peel which was higher by more than 2 folds than the control (without pectinase) with 0.42% (w/w) polyphenol yield. Mango seed powder/flour was also produced from mango seed waste and utilized in production of polyphenols. A yield of 107-108 mg GAE/g dry matter was obtained which was higher than reported yield in literatures. Phenolic extracts from mango peel and seed kernel exhibited significantly higher DPPH free radical scavenging activity and reducing power than synthetic antioxidants, butylated hydroxy anisole (BHA) and butylated hydroxy toluene (BHT). The result may indicate that the phenolic extracts are more potent antioxidants than BHA and BHT. Results of the acute oral toxicity test of phenolic extract from mango seed in mice may indicate that the extract was non-toxic. Crude extract of polyphenols was utilized in skin-care products such as lotion and hand sanitizer. Initial antimicrobial test on hand santizer with polyphenols showed inhibitory activity against common skin microorganism. Staphylococcus aureus, while the commercial hand sanitizer tested had none. Escherichia coli and Salmonella typhimurium were similarly inhibited. Dermal/toxocity test in rabbits showed that the hand sanitizer with phenolic extract was non-irritating and non-toxic on skin. Production of mango kernel flour (MKF) recorded an average yield of almost 40% from fresh kernel. Cost and return analysis of MKF production showed that processing the seeds into flour may be economically viable if production will be on a scale of at least 1,000 kg kernel/per run following the assumptions presented. The study on the functional properties of mango kernel flour showed that its bulk density was similar to commercial flour, had poor foaming ability and stability, and had lower emulsifying activity than commercial flour. But it showed good water holding and oil holding capacities which indicate its suitability in dough and pastry products. Mango kernel flour (MKF) was utilized in oatmeal cookies and 50% substitution of the flour with MKF resulted in healthier cookies with high phenolic antioxidants and acceptable as the commercial one. The cookies with MKF were microbiologically safe until the last sampling period of 35 days. The polyphenol levels in the cookies were also stable up to the 46 days. But some of its sensory attributes declined with long storage especially the texture or crispiness which may be due to lack of additive that preserves this attribute for long period. Mango peel powder was also produced and utilized as bakery ingredient but it has lower polyphenol content than mango seed flour. Hence, with regard to increasing the antioxidants in oatmeal cookies, mango kernel flour is better to use than mango peel powder even though sensory results showed that oatmeal cookies with mango peel powder were also acceptable.