No abstract

To enrich the berry product variety and improve the edible quality of blue honeysuckle berry (BHB), on the basis of determining the mixture recipe of the BHB pulp, fructose, and yoghurt (BHBY), the combined technology of microwave vacuum concentration (MVC) and freeze‐drying (FD) was proposed to produce novel BHBY snack. The results showed that the highest retention rate of anthocyanin content was 94.83% under a vacuum pressure of −0.05 MPa and a temperature of 50°C. The optimal FD parameters for the concentrated BHBY were determined as critical moisture content of 1.89 g/g (dry basis), material thickness of 13 mm, and desorption temperature of 36.9°C with a snack of hardness of 1,943.9 g, brittleness of 604 peaks, L* value of 36.7, and a* value of 20.7. The final BHBY snack presents acceptable taste with crispy texture and desired color. The developed processing technology is feasible for BHB snack. Practical applications This work developed a novel BHB snack by the application of MVC followed by FD technology and optimized the processing technology to achieve the desired product with high drying efficiency, preferable texture taste, and considerable retention of anthocyanin content. The recipe of BHBY and the processing technology proposed was beneficial for improving the edible quality of BHB. Further, it may provide guidance for the development of novel snack and deep processing of berry fruits like BHB.

Raspberry snack, as a novel berry product, has rich favor and high crisp taste, where controllable texture quality is conducive to the palatability of the snack. Determinative factors of microwave puffing in microwave intensity and durationand key property of material in Young's modulus were introduced to investigate the formation of texture quality of berry snack under microwave puffing. The results indicate that the microwave intensity has negative correlation with Young's modulus of raspberry chips, which causes the more porosity inside under microwave puffing. Reasonable Young's modulus of raspberry chips enhances the interior porosity and exterior expansion volume of raspberry snack due to the water vapor wrapped other than escaped. The greater microwave intensity results in the higher volume expansion of raspberry chips, in which the great volume expansion from porous pores structure confers moderate hardness. In microwave puffing, the formation of hardness and crispness of raspberry snack depend on microwave puffing parameters, leading to high temperature and great dehydration rate in quick puffing duration, in addition to Young's modulus of raspberry chips, where high dehydration rate accelerates water removal inside raspberry chips to form a harder texture with decreasing springiness, whereas low dehydration rate leads to the gentle change of springiness. Raspberry snack with uniform internal pores and regular shape forming desirable texture may be achieved under the microwave intensity of 7.5 W/g and the puffing duration of 6 min. This study indicates that high-quality raspberry snack may be achieved via controlling heating rate in microwave puffing.