Ultrasonication assisted process for crystal size reduction of honey from Nepal and evaluation of their bioactive properties | |
| Author | Karki, Anusha |
| Call Number | AIT Thesis no.FB-22-03 |
| Subject(s) | Honey--Nepal Bioactive compounds |
| Note | A thesis submitted in partial fulfillment of the requirements for the degree of Master of Science in Food Engineering and Bioprocess Technology |
| Publisher | Asian Institute of Technology |
| Abstract | Honey crystallization is a natural process that is generally not preferred by consumers and food manufacturers due to its difficulty in handling. A solution which is cheap, natural and easy to perform with less time is needed to speed up liquefaction and avoid formation of crystals in honey. In this study, the physicochemical and bioactive properties of eighteen different species of honey samples from Nepal's Central and Western regions were investigated. The two varieties of honey (Monofloral and Himalayan honey) were examined as per International Honey Commission methods. The findings revealed that all values, except moisture content in a few samples, align with current Nepalese and CODEX standards. Depending upon the bioactive components and other physicochemical properties, Buckwheat and Rudilo honey were found to be the best among eighteen different honey samples. The highest polyphenol content of these honey was reported to 236.71 ± 4.37 mg/GAE/100g followed by 88.16 ± 9.82 mg/GAE/100g respectively. The viscosity of honey measured at 50 rpm with Spindle no. 64 was temperature dependent and differed significantly (p<0.05) at four different temperatures (30, 35, 40 and 45⁰C). Among 18 samples, the samples with high glucose content 48.14 ± 1.52% for Rapeseed A and 39.82 ± 4.76% for Rukum A was chosen from each variety (Monofloral and Himalayan honey). The two selected samples were liquefied by an ultrasonic probe at different amplitude 40, 60 and 80 % for 10, 20 and 30 minutes. Result showed that Ultrasonication Assissted treatment with 80% for 30 minutes gives the best result with crystal size 113.00 ± 0.16 mm, 243.01 ± 0.28 mm for Rukum A and Rapeseed A respectively without altering the physicochemical and bioactive properties of the samples. Moreover, some significant increase in the polyphenol, flavonoids and antioxidant activity were reported after ultrasonication assisted treatment. The four types of honey having best polyphenol content were further analysed for antibacterial property which showed that all selected honey at 100% showed inhibitory effect against Staphylococcus aureus and Escherichia coli. |
| Year | 2022 |
| Type | Thesis |
| School | School of Environment, Resources, and Development (SERD) |
| Department | Department of Food, Agriculture and Natural Resources (Former title: Department of Food Agriculture, and BioResources (DFAB)) |
| Academic Program/FoS | Food Engineering and Bioprocess Technology (FB) |
| Chairperson(s) | Anal, Anil Kumar |
| Examination Committee(s) | Loc Thai Nguyen;Bhujel, Ram C. |
| Scholarship Donor(s) | ADB-JSP Scholarship |
| Degree | Thesis (M. Sc.) - Asian Institute of Technology, 2022 |