How to improve bayberry (Myrica rubra Sieb. et Zucc.) juice flavour quality: effect of juice processing and storage on volatile compounds.

To improve the flavour quality of bayberry juice, effects of different raw materials, heat treatment and storage time on the flavour variations were investigated. Changes of total sugar and titratable acids were also monitored. Identification and quantitation of volatile flavour compounds were performed by headspace solid-phase microextraction couped with gas chromatography-mass spectrometry (HS-SPME-GC-MS). The contents of esters, alcohols, total sugar and titratable acidity of the rancid flavour raw juice were 6.03%, 8.24%, 5.56 g/L, 0.18 g/L less than those of pleasing flavour raw juice (PF), while the content of aldehydes was 4.19% higher than that of PF. After 9 months storage, the bayberry juice produced fermentation-like flavours with alcohols increases (11.45%) while esters (14.91%) and total sugar (3.27 g/L) decreases. The results suggested that proper juice processing and storage techniques are critical to the flavour quality of bayberry juice.

Study of the optimisation of puffing characteristics of potato cubes by spouted bed drying enhanced with microwave.

BACKGROUND: In commercial deep-fat frying of potato chips, the oil content of the final products ranges from 35 to 45 g 100 g(-1) (wet basis). High-temperature frying may cause the formation of acrylamide, making the products unhealthy to the consumer. The aim of this research was to explore a new method, spouted bed microwave drying, to produce healthier puffed snack potato cubes as possible alternatives to oil-fried potato chips. The influence of drying conditions of the spouted bed microwave drying on puffing characteristics of potato cubes were studied and compared with the direct microwave and hot air drying method. RESULTS: Tandem combination drying of microwave-enhanced spouted bed drying (MWSB) could achieve a good expansion ratio, breaking force and rehydration ratio. The puffing characteristics of potato cubes were significantly affected (P < 0.05) by moisture content before starting microwave power in spouted bed microwave drying, by microwave (MW) power, and by the original size of potato cubes. CONCLUSION: The optimum processing parameters were the moisture content at the start of microwave power (60%), the size of potato cubes (10-12 mm), and microwave power (2-2.5 W g(-1))