Ultrasonic Cutting as a New Method to Produce Fresh-Cut Red Delicious and Golden Delicious Apples

The fresh-cut or sliced apple market has grown rapidly in recent years due to consumers' demand for fresh, convenient, and nutritious foods. Fresh-cut apples also contributed to increased consumption of fruits among school children. However, not many studies have investigated means to improve the quality of fresh-cut apples. In this study, we explored the use of ultrasound as a new method to cut apples and examined the quality of two apple varieties (Red Delicious and Golden Delicious) cut with ultrasound. Both apple types were cut without (control) and with ultrasound at four amplitudes (0%, 30%, 40%, and 50%) with an ultrasonic knife. Quality attributes, for example, color, pH, polyphenol oxidase (PPO) activity, surface morphology, and sensory characteristics (color, odor, overall acceptability, and off-odor) of the apples right after cutting and during a 2-week storage at refrigeration temperature were compared. With the set up used in this study, both apples cut with ultrasound exhibited a relatively dense and smooth surface morphology with less cell damage compared with the relatively rough surface and more cells damage in the control. An improvement in quality attributes was observed when the ultrasound amplitude was increased from 30% to 50%. The apples cut with ultrasound had a lower PPO activity compared to the control, indicating less browning. In visual quality evaluation, panelists showed higher liking of the apples cut with ultrasound. The ultrasound-assisted cutting has showed promise for producing fresh-cut apples with improved quality, and may be used as an alternative to traditional cutting method. PRACTICAL APPLICATION: Fresh-cut produce has gained popularity in recent years due to its health benefits. Traditional methods to produce fresh produce use a static stainless steel blade to cut fruits or vegetables, causing chemical or visual quality issues. This study proposed a new method using a blade that vibrates at ultrasonic frequency to cut apples. The results have shown an improvement in the quality of fresh-cut apples. This method may provide a new solution for producing fresh-cut produce to better meet the requirement of consumers for quality products.