Preparation Of β-cyclodextrin Inclusion Complex Of Lemon Peel Essential Oil And Its Application In Preservation Of Chilled Pork

With the increasing concern for sustainable development and food safety,the extraction of essential oils from waste fruit peels for food preservation has become a hot topic in research.In order to develop a natural food preservative for the preservation of chilled pork,this paper extracts lemon peel essential oil from waste lemon peel,and then prepares β-cyclodextrin inclusions from lemon peel by ultrasonication,and investigates the encapsulation effect and storage stability of the inclusions.The main elements are as follows:(1)Comparison of the effects of natural air drying(NAD),hot air drying(HAD),microwave drying(MD)and vacuum freeze drying(FD)on the sensory quality,bulk density of lemon peel powder as well as the extraction rate,antibacterial and antioxidant effects of lemon peel essential oil.The results showed that the FD group retained the best colour and aroma of lemon peel;the extraction rate and bulk density of essential oil were not significantly different among the FD,HAD and NAD groups,but they were all significantly greater than those of the MD group(p<0.05);the essential oil of lemon peel in different drying groups had strong inhibitory effects on common pathogenic and spoilage bacteria in pork,and the FD group had the best inhibitory effect;the antioxidant activity of the FD group was significantly greater than that of the HAD,NAD and NAD groups.The antioxidant activity of the FD group was significantly greater than that of the HAD,NAD and MD groups(p<0.05).(2)Using the inclusion rate as the index,the best preparation process for the preparation of inclusion by ultrasonication was obtained by single-factor test and response surface optimization test: ultrasonication time 40 min,ultrasonication temperature 44 ℃,ultrasonication power 180 W,core-to-wall ratio 1/12,and the inclusion rate was 73.24% under these conditions.Compared with the co-precipitation method,the cladding time was reduced by 77.7% and the cladding rate was increased by 9.45%.(3)The inclusions were characterised by scanning electron microscopy(SEM),particle size,X-ray diffraction(XRD),Fourier infrared spectroscopy(FI-TR),differential scanning calorimetry(DSC)and thermogravimetric analysis(TGA),and the effects of temperature,humidity and light conditions on the storage stability of the inclusions were investigated using the essential oil residue rate of the inclusions as indicators.the SEM results showed that The XRD results showed that some of the crystalline diffraction peaks of β-CD disappeared when the essential oil of lemon peel entered the inner cavity of β-CD;the FT-IR results showed that the intensity of the characteristic peak of EO in the spectra of the inclusions was reduced and red-shifted,confirming the formation of the inclusions;The DSC and TGA results showed that the thermal stability of the essential oil of lemon peel increased after it was successfully encapsulated in β-CD.Storage stability tests showed that the essential oil release rate was lowest at 4°C and highest at 50°C.The release rate of the essential oil under sheltered conditions was lower than that under natural light conditions,and the release rate of the essential oil under98% relative humidity was higher than that under 75% relative humidity conditions.(4)The p H value,total bacterial count,TVB-N value,TBARS value,colour difference and sensory score of chilled pork were used as indicators to compare the freshness preservation effects of lemon peel essential oil,β-cyclodextrin and lemon peel essential oil β-cyclodextrin inclusions on chilled pork.The lemon peel essential oil β-cyclodextrin complex was able to protect and delay the release of lemon peel essential oil,extending the shelf life of chilled pork by 4 d.The results of these studies indicate that the FD method is suitable for the storage,transport and extraction of essential oils from lemon peel,and that the extracted essential oils have strong antibacterial and antioxidant properties.The inclusions were prepared by ultrasonication in a shorter time and at a higher inclusion rate,making them more suitable for industrial production.The prepared inclusions are suitable for storage and transportation at low temperatures,low humidity and protection from light,and are more suitable for use as food preservatives at low temperatures,high humidity and light conditions.The inclusion compounds were able to extend the shelf life of chilled pork by 4 d.