Browning control of fresh-cut Chinese yam by edible coatings enriched with an inclusion complex containing star anise essential oil
Star anise essential oil (SAEO) has a variety of antioxygenic and antimicrobial properties, and is widely used in food preservation. However, its application is still challenging due to poor water solubility and physicochemical stability. We now report that encapsulation of SAEO in hydroxypropyl-β-cyclodextrin (HPCD) enhances its water solubility, as well as its thermal, storage, and photostability. The solubility of SAEO encapsulated by HPCD was increased by 47.5 times at 45 °C, and the onset temperature of thermal volatilization was delayed by at least 200 °C. The encapsulated material is also more uniformly and more stably dispersed in xanthan gum, and is thus released in a controlled manner. Importantly, fresh-cut Chinese yam coated with xanthan gum containing encapsulated SAEO is more effectively preserved, as assessed using weight loss, L* value, browning index, and polyphenol oxidase activity. The data suggest that the encapsulated SAEO reduced the weight loss of the samples by more than 30%, and the encapsulation of HPCD increased the inhibitory effect of SAEO on browning and polyphenol oxidase activity of the samples by nearly 8 times and more than 7 times, respectively. Collectively, SAEO encapsulated in HPCD is promising as a preservative coat for fresh-cut fruits and vegetables.