Date of Graduation
Davis College of Agriculture, Natural Resources and Design
Agricultural and Resource Economics
Improving Osmo-convective Dehydration as a Processing Technique to Food Preservation, Quality Enhancement, and New Product Development Felix Umaizimede Akharume This thesis is organized into five chapters. Chapter 1 contains a contains background information review of literature on osmo-convective drying of fruits, as well and nutrition, microbiology, and sensory attributes, Chapters 2 through 4 are three journal articles presented in the manuscript style. While chapter 2 is already published chapters 3 and 4 are prepared for submission to scientific journals. The chapter 2 addresses the use of apple juice concentrate as an alternative to the conventionally use of sugar solution in osmotic dehydration(OD) and convective drying of blueberries (fresh and frozen). OD was carried out at 50 °C, atmospheric pressure and 50 rpm. Follow up convective drying was set to 70 °C. Sugar gain, water loss, solid gain and OD yield were the parameters measured to compare the effect of these treatments. Additionally, desorption isotherm of fresh and frozen blueberries was measured to ascertain the role of freezing prior to OD and from these data the effective diffusion coefficient was estimated. The key points from the experiments reveal that fresh blueberries are not effective in OD. The use of apple juice experimentally did reflect a gain in solid, water loss and yield and as such can be used as an alternative. However, cost implication is not considered here.;Chapter 3, explored the use of sucrose with or without addition of food grade refined liquid smoke (RLS) in osmotic dehydration of apple cubes. Osmo-dehydration kinetics of solid gain, water loss, dry matter content, solid soluble content as well as effective diffusion coefficient of water loss or solid gain were measured or estimated. The methodology was similar to experiment reported in chapter 2 with slight modification, but detailed in this report. The results showed that sampled osmosed in sucrose solution with 1%w/w RLS significant recorded a higher solid gain water loss, dry matter, and solid soluble content. Again, average effective diffusion coefficient on water loss was the same for both samples, but average effective coefficient on solid gain was higher in samples osmosed in sugar solution without 1% w/w RLS.;Chapter 4 expanded on the methodology and data from chapter 3. Here dried apple slices were using experimental procedure described in chapter 3. The apple slices were analyzed for microbial growth, texture, and color quality to ascertain the effect of the addition of 1%w/w RLS on these sensory attributes. Results showed that dried apple slices pretreated in pure sugar solution retain the color of fruit better than untreated dried samples, while samples infused with RLS showed a characteristic brown coloration. Additionally, RLS infused dried apples showed the highest textural properties and control showed the lowest. In all samples, significant microbial reduction (below 5 log CFU/g) was recorded throughout storage period. However, RLS infused dried apples showed the highest microbial growth reduction and the control showed the lowest microbial growth reduction in a non-vacuum package.;The last chapter, chapter 5, summarizes the major finding in these studies and recommends area of future expansion. In addition, raw data and statistical analysis of experimental data are presented in the appendix.
Akharume, Felix Umaizimede, "Improving Osmo-convective Dehydration as a Processing Technique to Food Preservation, Quality Enhancement, and New Product Development" (2017). Graduate Theses, Dissertations, and Problem Reports. 5041.