Screening Of Antifungal And Fresh-keeping Activity Of28Botanical Extracts On Fruits And Vegetables

Preservation is an urgent problem for postharvest fruits and vegetables during storage,transportation and sale. As an important component of fresh-keeping measures, botanicalpreservative agents are non-toxic, harmless and non-residue, are safe for human beings,animals and natural enemies, and well compatible with environment, compared with chemicalpreservative agent, which have incomparable superiority. Therefore, botanical antifungal andfresh-keeping agents are becoming a research hotspot in fresh-keeping field.The experiment was conducted at room temperature (RT), and the relative humidity wasapproximately85%. Taking Qinmei kiwifruit, Fuji apple fruit and tomato fruit asexperimental fruits and vegetables, the antifungal and fresh-keeping effectiveness of28kindsof botanical extracts was screened. Then, the preservative effects of the botanical extractswhich have preliminary antifungal and fresh-keeping activity were tested comprehensively.The primary conclusions were as follows:1. The preliminary antifungal and fresh-keeping activity of14kinds of botanical extractson Qinmei kiwifruit was tested with immersion method. The screening experiment showedthat, tea seed oil made an efficient activity. Then, the antifungal and fresh-keeping activity oftea seed oil was symtemically determined with4concentration gradients during62.5μL L^-1～500μL L^-1. The results showed that, weightloss, soften rate and rotten rate were3.36%,16.04%and6.90%respectively after a50-day storage (RT). The activities of SOD, POD andCAT enzyme, Vc content and firmness were significantly larger than CK during storage; Thepeak of CO₂and enthylene respiration were significantly smaller than CK. The resultsdemonstrated that,500μL L^-1tea seed oil treatment made a significant preservation effect,and the comprehensive effect was prior to CK and1-MCP.2. The preliminary antifungal and fresh-keeping activity of27kinds of botanical extractson Fuji apple fruit was tested with immersion method. The preliminary screening resultsshowed that, star anise oil made an efficient activity. In order to confirm the optimumconcentration (OC), the antifungal and fresh-keeping effect of star anise oil was carried outunder4concentration gradients between62.5μL L^-1and500μL L^-1. The results showed that,under125μL L^-1, the antifungal and preservation effect of star anise oil preservative on Fujiapple fruit was the best, within the range of tested concentration. Then, the sensor index,physical and chemical quality of Juji apple fruit were tested during storage after treating with 125μL L^-1star anise oil treatment. The results demonstrated that,125μL L^-1star anise oiltreatment made a significant preservation effect, weightloss and rotten rate were3.22%and15.70%respectively after a120-day storage (RT). The activities of SOD, POD and CATenzyme, Vc content and firmness were significantly larger than CK during storage; The peakof CO₂respiration was significantly smaller than CK, and the peak of enthylene was delayed20days; Therefore, the comprehensive effect was about the same with1-MCP, prior to CK.3. The preliminary antifungal and fresh-keeping activity of20kinds of botanical extractson tomato fruit was tested with immersion method. The preliminary screening results showedthat, star anise oil, geraniol, cinnamic aldehyde etc.15kinds of botanical extracts made anefficient activity. In order to confirm OC, the antifungal and fresh-keeping effects of the15botanical extracts were tested again under4concentration gradients in the testedconcentration range (essential oil125～1000μL L^-1, and the other1～10mg DW ml^-1). Theresults showed that, a significant antifungal and preservative effect was made by cinnamicaldehyde, geraniol, star anise oil, red-rooted salvia extract and mint extract, whose OC was125μL L^-1,125μL L^-1,125μL L^-1,1mg DW mL^-1and2.5mg DW mL^-1, respectively. Then,the sensor index, physical and chemical quality of Jinpeng tomato fruit were tested duringstorage after treating with the5botanical extracts under OC, respectively. The resultsdemonstrated that,2.5mg DW ml^-1salvia miltiorrhiza extracts treatment made a significantpreservation effect, the activities of SOD, POD and CAT enzyme, Vc content and firmnesswere significantly larger than CK during storage; The peak of CO₂respiration was delayed8days; So the comprehensive effect was prior to CK and1-MCP.