Blueberries are well known for their high anthocyanin content and the health benefits. Fresh blueberries have limited shelf life and thus are kept frozen or processed. Since freezing is expensive, low cost processing methods, particularly drying are being devised. Various drying treatments were compared with regard to drying time and quality of the dried product in terms of anthocyanin and polyphenolic contents as well as antioxidant activity. The drying treatments involved high temperature in a cabinet dryer and low temperature in a heat pump dryer. Freeze drying was used as a reference treatment. Highbush (Vaccinium corymbosum L., cultivars Crunchie, Star, and Sharpe) and rabbiteye (Vaccinium ashei, cultivars Climax, Powderblue, and Brightwell) blueberries were used in this study. Pre-treatments included osmotic dehydration or skin abrasion. The temperature and concentration of the osmotic solution were the main parameters contributing to the reduction of drying time. Mechanical skin abrasion was more effective than osmotic dehydration in reducing drying time and minimising the loss of anthocyanin and phenolic contents of the blueberries in air drying treatments. The thickness of cuticle and the structure of epicuticular waxes affected the drying rate of different cultivars of blueberries. Liquid chromatography and mass spectrometry (LC/MS) was used to identify different anthocyanins in the blueberry samples. Delphinidin, petunidin, and malvidin were the main contributors to the total anthocyanin content of the fresh and dried samples. Degradation products of anthocyanins were observed in samples where the anthocyanin contents declined as a result of drying treatments. The anthocyanin content and profile, phenolic content, and antioxidant activity of mulberries (Morus nigra), and Makiang (Cleistocalyx nervosum), a Thai native fruit, were also analysed. There was no significant difference between total anthocyanin content of blueberries and mulberries. In contrast, the total phenolic content and antioxidant effect of mulberry were significantly higher than those of blueberries and Makiang. Skin abrasion and high temperature drying resulted in the fastest drying rate and highest anthocyanin retention. Anthocyanin profiles differed in various cultivars of blueberries. Within the same cultivar, amounts of each anthocyanin varied with pre-treatments and drying methods but the distribution of monomeric anthocyanins was similar.

This item was digitized as part of the Million Books Project led by Carnegie Mellon University and supported by grants from the National Science Foundation (NSF). Cornell University coordinated the participation of land-grant and agricultural libraries in providing historical agricultural information for the digitization project; the University of Arizona Libraries, the College of Agriculture and Life Sciences, and the Office of Arid Lands Studies collaborated in the selection and provision of material for the digitization project.

No description available.

Vitamin K₅, 4-amino-2-methyl-1-naphthol hydrochloride, a water soluble analog of vitamin K has been shown to possess an antimicrobial activity toward many bacteria, molds, and yeast. Much of the work reported in the literature is on its use as a food preservative, and it was the purpose of this study to investigate some of the factors which might affect the antimicrobial activity of vitamin K₅ in order to add insight into its more effective use as a food preservative. Pure cultures of Escherichia coli, Bacillus subtilis, Proteus vulgaris, Staphlococcus aureus, and Pseudomonas fluorescens were utilized. The effect of the method of application of vitamin K₅ on Escherichia coli; the effect of purity of vitamin K₅ against Escherichia coli; the bactericidal concentrations required for Escherichia coli, Bacillus subtilis, Proteus vulgaris, Staphlococcus aureus, and Pseudomonas fluorescens; the effect of an absence of oxygen; the effect of contact time with Escherichia coli; the effect of initial count/ml of Escherichia coli; and the synergistic action in combination with propylene glycol were studied. The results demonstrated that air oxidation of vitamin K₅ was necessary to obtain maximum inhibitory activity against Escherichia coli. The use of white, crystalline vitamin K₅ synthesized in the laboratory, as compared to partially oxidized commercial preparations, gave better results against Escherichia coli. It was shown that some species variation, with the five microorganisms tested, did exist with respect to the antimicrobial activity of vitamin K₅. The bactericidal concentrations ranged from 60 ppm for Staphlococcus aureus to 220 ppm for Escherichia coli, using an initial count of 160,000 to 200,000 cells/ml and a contact time of 12 hours in Bacto-nutrient broth. The gram-positive bacteria tested were more susceptible to the antimicrobial activity of vitamin K₅ than the gram-negative bacteria tested. In the studies conducted under nitrogen atmosphere the percent inhibition showed an inverse relation to the bactericidal concentrations required for complete inhibition in studies conducted under air atmosphere. This finding suggested that there might be different factors responsible for inhibition depending on the species of bacteria being tested and also might help explain the difference in concentrations necessary for inhibition. Cells of Escherichia coli were not inhibited immediately on coming into contact with vitamin K₅. Fifty percent inhibition occurred after 25 minutes. A rapid inhibition rate was maintained until approximately 90 percent inhibition occurred, afterwhich, a rapid decrease in the rate of inhibition was noted. An increase in the initial number of cells of Escherichia coli utilized required an increase in the concentration of vitamin K₅ for complete inhibition, although the concentration of vitamin K₅ was not the limiting factor. A synergistic effect does exist between vitamin K₅ and propylene glycol, and the bactericidal concentrations necessary for the different bacteria can be reduced depending on the species of bacteria and the concentration of propylene glycol utilized. / Graduation date: 1965

Graduation date: 1948

Blueberries are well known for their high anthocyanin content and the health benefits. Fresh blueberries have limited shelf life and thus are kept frozen or processed. Since freezing is expensive, low cost processing methods, particularly drying are being devised. Various drying treatments were compared with regard to drying time and quality of the dried product in terms of anthocyanin and polyphenolic contents as well as antioxidant activity. The drying treatments involved high temperature in a cabinet dryer and low temperature in a heat pump dryer. Freeze drying was used as a reference treatment. Highbush (Vaccinium corymbosum L., cultivars Crunchie, Star, and Sharpe) and rabbiteye (Vaccinium ashei, cultivars Climax, Powderblue, and Brightwell) blueberries were used in this study. Pre-treatments included osmotic dehydration or skin abrasion. The temperature and concentration of the osmotic solution were the main parameters contributing to the reduction of drying time. Mechanical skin abrasion was more effective than osmotic dehydration in reducing drying time and minimising the loss of anthocyanin and phenolic contents of the blueberries in air drying treatments. The thickness of cuticle and the structure of epicuticular waxes affected the drying rate of different cultivars of blueberries. Liquid chromatography and mass spectrometry (LC/MS) was used to identify different anthocyanins in the blueberry samples. Delphinidin, petunidin, and malvidin were the main contributors to the total anthocyanin content of the fresh and dried samples. Degradation products of anthocyanins were observed in samples where the anthocyanin contents declined as a result of drying treatments. The anthocyanin content and profile, phenolic content, and antioxidant activity of mulberries (Morus nigra), and Makiang (Cleistocalyx nervosum), a Thai native fruit, were also analysed. There was no significant difference between total anthocyanin content of blueberries and mulberries. In contrast, the total phenolic content and antioxidant effect of mulberry were significantly higher than those of blueberries and Makiang. Skin abrasion and high temperature drying resulted in the fastest drying rate and highest anthocyanin retention. Anthocyanin profiles differed in various cultivars of blueberries. Within the same cultivar, amounts of each anthocyanin varied with pre-treatments and drying methods but the distribution of monomeric anthocyanins was similar.

No description available.

The refrigeration energy load in a modern day supermarket makes up a large proportion of the total energy bill. Better design of refrigerated display cases would reduce this load and also have a corresponding effect on the running costs of the refrigeration plant. Further enhancements such as the reduction of air overspill from the case would also influence the aisle temperatures and therefore the comfort levels in the store. This research project uses the technique of computational fluid dynamics (CFD) to investigate the contemporary design of a vertical multideck refrigerated display case. From a two dimensional computational model conclusions were drawn as to the principles of operation of the case. During the course of the project, a custom designed experimental facility was constructed, capable of testing the display case according to the relevant test standards. Using this facility, experimental validation was carried on a number of the design modifications to assess the actual refrigeration load against that predicted by the CFD model. The success of this validation allowed further work into the feasibility of certain design changes by making modifications to the CFD model. The work presented in this thesis makes a contribution to the global effort towards the reduction of the energy consumption by retail refrigeration systems. It does this by showing that possibilities do exist for an improvement in the energy efficiency of multideck refrigerated display cases and that CFD provides a useful tool towards this goal. It also demonstrates the design modifications which proved to yield a saving in energy. These were a reduction in the mass flow rate of air around the case, the inclusion of a honeycomb section on the air curtain outlet of the case the addition of a front upstand and the introduction of a second air curtain thus applying a velocity gradient across the curtain.

No description available.

The application of ionizing radiation as a preservation method for food is described and examined. The prospects and problems of introducing radiation technology for food preservation are discussed under the following aspects: (1) technical feasibilities; (2) irradiator design requirements; (3) facilities' cost analysis, and (4) legislation. Within the specified limits, ionizing radiation provides an efficacious food preservation treatment which will not lead to radioactivity induction or prejudice the safety and wholesomeness of the food. A brief introduction and description of the design approach of an industrial scale irradiator is given with an illustrative example. Assessments of the cost of radiation treatment of food of some commercially available irradiators are cited and analyzed. The international regulatory efforts and the present status of clearance, standardization and legislation of food irradiation is reviewed and discussed. It is concluded that food irradiation is ready for commercial applications and could be effectively regulated by pertinent health and safety authorities.