Optimising Microwave Vacuum Puffing For Blue Honeysuckle Snacks

Fresh blue honeysuckle fruit slices were puffed in a microwave vacuum dryer up to a final moisture content about 5% (w.b.). The effect of initial moisture content (IMC) (25-45%), vacuum pressure (VP) (70-90 kPa) and microwave intensity (MI) (10-30 W g-1) on quality attributes, in terms of expansion ratio (ER), hardness (HD), crispness (CR) and colour of the products, were analysed by response surface methodology. Besides the effect of MI on chroma (CH), the high IMC and low VP had a significantly positive impact on the quality attributes of blue honeysuckle snacks. The optimum product qualities, which were ER (1.62 times), HD (5836.31 g), CR (4.48), and CH (28.7) were obtained at an IMC of 38.42%, VP of 82.02 kPa, and MI of 22.42 W g-1. The microwave vacuum method has obvious advantages when puffing the blue honeysuckle snacks.