More than 27% of total phenolics were lost in blanched refiner. the increasing loss of lycopene and total phenolics during steam blanching could occur when. Keywords: Enzymatic browning, dipping, blanching, coating, preservation. Introduction. Fruit and vegetables have health benefits for consumers, due to their. Abstract. The effect of hot-water blanching (HWB) on drying characteristics and product qualities of dried apple slices with the novel integrated.
|Published (Last):||24 January 2017|
|PDF File Size:||9.23 Mb|
|ePub File Size:||17.94 Mb|
|Price:||Free* [*Free Regsitration Required]|
Article Metrics Abstract views: Then, measurements of pores area obtained from binarized images were carried out by the Image Pro-Plus software Media Cybernetics, Inc. The samples were then pruned and cut into thin slices by using an LKB ultramicrotome.
Pengaruh Blanching terhadap Sifat Antioksidasi Sirup Kunir Putih (Curcuma Mangga Val.) – Neliti
Before HWB pretreatment, cell wall and membrane were tightly bonded with each other, and the cell membrane was thick, intact, and continuous in shape and dimension. Cin Chinese, C, In an effort to reduce drying time, researchers attempted to combine FD with other drying methods including vacuum drying, microwave drying, and osmotic drying, and they had achieved good effect in the laboratories [ 46 ]. Abstract Purple Dioscorea alata DA tuber has health benefits due to its bioactive anthocyanins, which belong to polyphenolic group.
How to cite item. However, further investigation should be carried out on the product quality especially how to maximally retain the original shape of freeze-dried samples. Structure, function and applications.
Mass loss blaanching an inevitable phenomenon for either the VF treatment or the PF treatment. It was found that mass loss of apple samples at the end of the VF treatment are much higher than that in the PF treatment because they were caused by completely different action principles. In conventional freeze-drying CFD processing line, blanchinh the individual steps require independent equipment or facility. The observed samples were placed on one surface of a two-sided adhesive tape that was fixed to the sample support.
Moreover, the water loss during vacuum freezing can reduce the subsequent sublimation load and the FD time. The microstructure of apple cell tissues was analyzed by transmission electron microscopy and scanning electron microscopy to interpret the above differences in drying characteristics and product qualities. Correspondence should be addressed to Hai-ou Wang ; moc. The measurements were carried out on 5 apple slice samples for each FD method and the average values were taken for analysis.
Micrographs were taken at x and x magnification. VF-FD samples formed the smallest pores and appeared to be the most compact and dense Figure 9 a. Each rehydration experiment was carried out in triplicate and the averages are reported.
Tuber is commonly made into flour to optimize its uses, however, the anthocyanins undergo significant degradation during processing because of the endogenous polyphenol oxidase activities.
Meanwhile, water content and water solubility index in the range 4. Finally, the samples were double-stained using uranyl acetate and lead citrate.
Journal of Food Quality
For example, materials after blanching should be quickly cooled with cold running water, drained with vibratory or centrifugal equipment, frozen with fluidized blanchimg freezer or cold storage, and then dried in vacuum freeze dryer. It is well known that ice crystal size is closely related to the freezing rate.
At the end of the freezing treatments in the above three processing methods, mass loss of apple slice was calculated by using the following formula: In Figure 9it can be found that the honeycomb network was formed in the tissues of all the samples. L value has decreased until Table of Contents Alerts. PHP Q u i c k Profiler. In order to obtain a successful FD performance, the fresh raw materials were required to be fully frozen and keep frozen temperature below their eutectic temperature.
The refrigeration machine also provides refrigerating output to the nurnal trap to condense the water vapor generated from food samples. How to cite item. User Username Password Remember me. The removed heat either from the material trays or from the plates due to the temperature difference before and after the VF treatment was absorbed mostly by the latent heat of water evaporation from apple samples. The sample volume was determined by the volumetric displacement method using glass beads with a diameter in the range 0.
The coordinates of the color CIE- lightnessrednessand yellowness of the skin of apple slice samples were obtained by reflection. Keywords anthocyanins, blanching; citric acid; dioscorea; polyphenols. There were 50 slices of apple in each group. PAU Pangan dan Gizi. In this study, two different freezing methods were carried out in the vacuum freeze dryer: Hardness of freeze-dried samples in 3 freeze-drying methods.
The fact that blanching pretreatment can lead to some soluble solid jufnal in fruits tissue had been verified by some available research literatures [ 3738 ]. Higher mass loss and more temperature decrease in HWB-VF-FD were more favorable for the NIFD process by considering the requirement of the fully freezing and the eutectic temperature of fresh samples as well as the least FD time as possible.
Figure 5 blanchihg the content of freeze-dried samples in the three methods. The vacuum condition is maintained by the vacuum pump. So the energy of water evaporation was not only dedicated to the cooling and freezing of apple samples.
When apple samples were frozen during the PF treatment, a small amount of dehydration also occurred due to the superficial ice sublimation caused by the vapor pressure-temperature environmental interaction [ 2728 ].
Besides, microvolume distribution of water in the apple tissue during the VF treatment can directly influence the size of ice crystal and the network pores. It can be concluded that HWB pretreatment was the main factor blandhing for the difference in contents, while the freezing method was not.
But in practice, conventional freeze-drying process is characterized by many disadvantages including complicated process steps, large space occupation, huge equipment investment, frequent materials transferring, long drying time, and high production cost, which greatly reduced economic competitiveness of FD products.