10 research outputs found

    The potential for a novel alcoholic drink prepared from the New Zealand native plant Cordyline australis (ti kōuka)

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    Some New Zealand indigenous plants may offer unique qualities that can be used to secure an exclusive niche in the alcoholic drinks market in the same way that Scotch whisky and tequila are strongly identified with the country of origin, Scotland and Mexico. Tequila is a spirit distilled from a fermented agave, dry adapted lily. Agave is in the family Agavaceae, a notable New Zealand member of which is the common cabbage tree or ti kōuka (Cordyline australis). Similarly, to the agave having a fermentable core, ti kōuka has carbohydrate (inulin) content in its young stems and roots that can be hydrolysed in acidic suspensions or by enzyme hydrolysis to yield fructose. The main objective of this thesis was to systematically research the feasibility of the production of a tequila-like spirit from ti kōuka stem, profiling the chemical properties of the spirit with a view of future commercial production of an iconic New Zealand spirit. The initial stage of the thesis focused on extracting inulin from the ti kōuka stem and hydrolysing (by both acid and enzyme) it to yield reducing sugar. The sugar concentration yielded was too low (~ 10 to 15%) to be fermented and distilled economically. Rather, the ti kōuka extract was evaporated to produce flavoured products by the Maillard reaction, a reaction between amino acids and sugars. The flavoured compounds were then infused with potable ethanol. In outline, the dried stem was hydrolysed with an inulinase at 60°C for 1 hour. The pH was adjusted to 10 with sodium hydroxide and evaporated at 60°C for 65 hours. The dried extract was reconstituted with water, centrifuged and the supernatant infused with portable ethanol to yield final different concentrations of 80, 67, 57 and 50%. The ethanol treatments simultaneously extracted flavour and colour to varying degrees. Next, sugars and amino acids were analysed in the ti kōuka stems by liquid chromatography. The most abundant sugar present in the ti kōuka after inulinase hydrolysis was fructose and the dominant amino acids were arginine, leucine, lysine, and aspartic acid/aspargine and glutamic acid/glutamine. Amino acids and reducing sugar were also analysed at different stages of the spirit production. The reducing sugar content decreased during each step of the process. The relative concentrations of arginine, leucine and lysine decreased while that of aspartic and glutamic acids increased during the whole process of making the spirit. Model systems were then used to simulate the reactions taking place between the amino acids and reducing sugar present in the ti kōuka extract. The colour of the models became darker as a function of time, accumulating more brown pigment containing the flavoured compounds. Increasing the pH and concentration of the amino acids in the reaction mixture also increased the browning pigment formation. Dichloromethane and n-pentane and diethyl ether solvent extraction of the spirits and analysis of volatiles by gas chromatography- mass spectrometry revealed that the chemical profiles of the spirits were different from those of the commercial spirits, gin, tequila and whisky. Sensory evaluation was performed on four variations of the spirit, and demonstrated that the creations were consumer-acceptable. The costs and other issues involved in producing and marketing such a spirit were identified, the major selling point being geographical exclusivity

    The laxative effect of kiwifruit

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    Background Whole fruits, grains and vegetables contain thousands of potential disease-fighting, healthpromoting nutrients. These foods play a critical role in bowel function, especially in the elderly. Strong epidemiological evidence has shown that greater amounts of crude dietary fibre are associated with a lesser prevalence of constipation and other gastrointestinal disorders. Constipation usually presents as a variety of symptoms, including reduced frequency of defaecation and impacted forms of stools and/or increased effort required to defaecate. Constipation is a problem that could affect any person at any time in his or her life, but in the elderly is more prevalent. Although anecdotal reports and dietary advice have suggested the use of kiwifruit as a laxative in humans, there are, at present no data available to support this. Kiwifruit is reported as the most nutrient-rich of the top 27 fruits eaten in the world today. The laxative property of kiwifruit could provide a natural remedy for constipation and would be cheaper than the laxatives on the market. Objective: The main objective of this study was to investigate if kiwifruit can act as a laxative, especially in elderly people. Study Design and Methods: This study was carried out in two stages, as a pilot and then a main study. In the pilot study, 71 participants (aged 18 – 50y) were divided into Group I and Group II. Group I made no changes to their normal diet for a six weeks period, while Group II were asked to add one kiwifruit for every 30kg body weight per day to their diet for a six week period. After the six weeks, the two experimental groups crossed over, maintaining the dietary regime followed by the other group for a further six weeks. So each subject was his or her own control. Daily recording of the frequency and characteristics of the stool were made by the participants in a diary. In the main study, 42 participants (aged 60 years and over) carried out the same dietary regime as the pilot study subjects. Elderly subjects of Group I made no changes to their diet, but was asked to record their daily frequency and characteristics of their stool for 3 weeks. Group II subjects ate one kiwifruit for every 30kg body weight per day for a period of 3weeks. After the three weeks period, the two groups crossed over. Results: It was found from the pilot study that kiwifruit consumption was associated with significant softening of the stool (P<0.001); a significant increase in bulking of the stool (P=0.034) and the ease of bowel movement was improved (P<0.001). For the main study, kiwifruit consumption also showed softening of the stool (P<0.001) and the ease of bowel movement was improved (P<0.001), there was a slight but significant increase in bowel frequency (P=0.012) and the bulking of stool (P=0.002). Conclusion: The results from this study provide evidence that consumption of kiwifruit enhances laxation and that bowel function can be improved through changes in diet, both for younger and elderly people

    Response of PSM Inoculation to Certain Legumes and Cereal Crops

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