No description available.

No description available.

It is shown that polymerized fructose present in tubers of Helianthus tuberosus L. is utilized in the growth of new plants; over a few weeks, tubers lost 8O% of their dry weight, fructose accounting for 8O% of this loss. The translocation of material from the tuber was accompanied by depolymerization of fructosan; this was consistent with the assumption that carbohydrate was transported in the form of sucrose. Depolymerization did not occur in tubers at 20°C which were not translocating material, but could be induced in dormant tubers by storage at low temperature (2-8°C). The mechanism of depolymerization in both these circumstances Was examined, and it is shown to be the same in each case; the evidence is consistent with the hypothesis that the first stage in the process is the liberation of free fructose from the fructosan. Two enzymes which catalyse the hydrolysis of fructosans found in the artichoke tuber were separated from tuber extracts. Their specificity appeared to be confined to the hydrolysis of the beta2-1 linkage between a terminal fructose and its adjacent residue, but in addition, the rate at which a particular sugar was attacked depended to a large extent on the number of residues it contained. The characteristics of one of these enzymes were investigated in detail, with particular reference to its possible role in the living plant: no properties were found which would preclude its being active in vivo; an important feature was found to he inhibition by sucrose which could represent a possible factor in the control of fructosan breakdown.

No description available.

No description available.

Jerusalem artichoke has been cultivated in various regions without any special breeding technique. On the other hand, in food industry it does not have a wide usage area. Hence, in food industry its use as a potato substitute in some products is believed to be increasing its economical value. As a first attempt chips and crisps produced from Jerusalem artichoke was analyzed for texture, sensory, color, oil and moisture content. Jerusalem artichoke chips were fried in a bench top deep fat fryer for 120s, 180s and 240s at 160&deg / C, 170&deg / C, 180&deg / C and 190&deg / C. When microwave oven was used samples were cooked for 60s, 75s, 90s, 105s, 120s, 135s and 150s at 600 Watt and 900 Watt. Rheological properties of Jerusalem artichoke puree were investigated and Xanthan gum (2%wb) and sodium metabisulphite (1%wb) added for the desired puree consistence and color. After the production of puree Jerusalem artichoke flour was produced and water added to this flour then dough obtained again. Rheological behaviour of the original puree and these prepared from the containing 1- 4.5 and 1 - 5.0 part water were quite similar. In the light of the experimental results obtained as frying temperature and treatment time increased, moisture content and lightness of the Jerusalem artichoke products have decreased but a*and b* values, hardness, fracture and oil content increased. The best results for frying of Jerusalem artichoke seem to be 180&deg / C with about 240s treatment time for the chips and the same temperature for 180s for the crisps. As microwave power level and duration of treatment increased, moisture content and lightness of the microwave cooked Jerusalem artichoke products have decreased, but a* and b* values increased. Hardness and fracturability values of the products first increased with time and then decreased. When microwave oven was used, the best results were obtained for about 105s treatment time at 600W for the Jerusalem artichoke chips and about 60s processing time at 900W for the crisp. Since treatment time for cooking was significantly reduced when microwave cooking was used, this method could be recommended as an alternative to conventional deep fat frying, as oil is not used as well.

Call number: LD2668 .T4 1978 L43 / Master of Science / Chemical Engineering

The development of processes for the preparation of prebiotic compounds, namely inulin from tubers of Jerusalem artichoke (JA-Helianthus tuberosus L.), and lactulose from milk concentration permeate (MCP) was examined. Inulin was extracted from the whole JA tubers using hydrothermal extraction process, followed by clarification and concentration. The concentrate was fractionated using two different procedures i.e. ethanol fractionation and cold precipitation (+4 and/or -24C) into high- and low-molecular-weight components. The most satisfactory method was cold fractionation wherein the insoluble heavier inulin fractions were found to settle to the bottom and were separated and spray-dried to obtain inulin powder. Lactose in MCP was isomerised into lactulose using carbonate-based catalysts (oyster shell and egg shell powders) followed by clarification and concentration. The high-performance liquid chromatography with refractive index detector (HPLC-RID) chr omatograms and changes in pH and colour values confirmed the conversion of lactose into lactulose and decomposition of lactulose into by-products. The results obtained showed the suitability of oyster shell powder for lactose isomerisation in lieu of egg shell powder. For preparing lactulose-enriched MCP with acceptable lactulose yield of 22%, the optimum reaction conditions were found to be catalyst loading of 12 mg per mL of MCP and isomerisation time of 120 min at 96C. The resulting products i.e. JAI concentrate and powder and lactulose-enriched MCP syrup (40B) were tested for their prebiotic power in media broth and in fermented milk models. Prebiotic properties of these compounds were observed as supplementation levels increased from 0-2% to 3-4%. Based on the growth and acidification abilities of the probiotic strains tested, the combination of Lactobacillus casei LC-01 with JAI, and Lactobacillus acidophilus LA-5 with lactulose-enriched MCP syrup were found to be the best for development of synbiotic yoghurt. The prebiotic effect of JAIP was then compared with the two commercial chicory inulin products (Raftiline GR and Raftilose P95). Probiotic yoghurts supplemented with 4% inulin powders were prepared from reconstituted skim milk using mixed cultures of Lactobacillus casei LC-01, Streptococcus thermophilus and Lactobacillus delbrueckii subsp. bulgaricus (1:0.5:0.5, w/w). The survival and acidifying activity of probiotic and lactic acid cultures were investiga ted during the shelf life of 28 days at 4C. Incorporation of JAIP and chicory inulins resulted in a significant improvement in viability of LC-01 compared with non-supplemented yoghurt, maintaining more than 107 CFU g-1 throughout storage time. Additionally, the suitability of JAIP as fat replacer was determined in a set of fat-free yoghurt in comparison to three commercial chicory inulin products. Results of large deformation tests revealed that the firmness of JAIP-supplemented yoghurt was reduced to a similar level as the full-fat control yoghurt. However, small deformation results showed that the JAIP could not fully mimic milk fat to the same extent as Raftiline HP with an average DP of 23. The rheological effects of JAIP addition were comparable to those of short-chain (Raftilose P95 with an average DP of 4) and medium-chain inulins (Raftiline® GR with an average DP of 12).

Extraction of fructo-oligosaccharide syrups from grated jerusalem artichoke (JA) tubers was studied by water at 20-60&deg / C by determining the yield, degree of polymerization (DP), product profile (DP of up to 6) and prebiotic effect using Lactobacillus plantarum on samples harvested between October and April, stored for 0-20 days. The optimum solvent to solid ratio was 4, the duration of shaking water bath extraction was 40 min and yield based on JA were 12-17%. Temperature was found to improve yield and functionality, and citric acid, at 26 mM, improved the color and darkness by 70 and 80%, respectively. Short-time (1 min) microwaving prior to extraction increased the yield by about 20%, decreased the amount of sugars with DP 1 and 2 and increased the amounts of oligosaccharides (OS) with DP 3-6, although the prebiotic effect increased only slightly / while the color and darkness of the syrup were tripled. Ultrasound-assisted-extraction (USE) gave best performance at 3 min duration / decreased the amounts of sugars with DP 1-2, increased the amounts of OS with DP 3-6, with 18% decrease in the yield. The better functionality of USE syrups were also indicated by 2.5 times higher growth rate of L.plantarum. The application of USE at 60&deg / C compared to 20&deg / C almost tripled the amounts of functional sugars. In order to obtain the largest proportion of monosaccharide units as functional sugars, 10 day storage at 4&deg / C after harvest was indicated. Ultrasonication did not affect the color but the darkness was doubled. The density and viscosity of all the syrups were practically the same.

Darbo objektas– topinambų gumbų veislės: 'Albik', 'Rubik', 'Sauliai'. Darbo tikslas – įvertinti topinambų (Helianthustuberosus L.) gumbų cheminės sudėties kitimą jų vegetacijos laikotarpiu. Darbo metodai – Topinambų gumbų cheminės sudėties tyrimai atlikti Aleksandro Stulginskio universitete Maisto žaliavų, agronominių ir zootechninių tyrimų laboratorijoje. Eksperimentas buvo atliktas 2012 m. Petro Tiknevičiaus ekologiniame ūkyje, kuris yra Alytaus apskrityje, Varėnos rajone, Geidukonių kaime, pietrytinėje Lietuvos dalyje, smėlingoje Dainavos aukštumoje ir Eišiškių plynaukštėje. Atliktas dviejų veiksnių eksperimentas: veiksnys A – topimanbo veislė, veiksnys B – gumbų vystymasis ontogenezės ciklo metu (mėnesiai). Mėginiai imti 8 kartus: kovo, balandžio, gegužės, birželio, rugpjūčio, rugsėjo, spalio, lapkričio mėnesisias. Topinambų gumbuose standartizuotais metodais nustatyta cheminė sudėtis: sausųjų medžiagų, tirpių sausųjų medžiagų, vitamino C, žalių proteinų, žalios ląstelienos, žalių pelenų, nitratų ir kalio kiekiai. Tyrimų duomenys statistiškai apdoroti dviejų veiksnių dispersinės analizės metodu, apskaičiuotas mažiausias esminis skirtumas (R05). Paskaičiuotas koreliacinis priklausomumas, bei determinacijos koeficientas naudojant kompiuterinę programą Stateng. Paskaičiuoti vidurkiai ir standartiniai nuokrypiai. Darbo rezultatai: 'Albik' veislės gumbuose esmingai daugiausiai sausųjų medžiagų (25,3%) nustatyta lapkričio mėnesį, t.y. XII organogenezės etapo metu, o tirpių... [toliau žr. visą tekstą] / Object of the research: varieties of Jerusalem artichoke tubers “Albik“, “Rubik“, “Sauliai“. Research methods: the analysis of chemical structure of Jerusalem artichoke tubers was performed in the laboratory of Raw Materials for Food, Zootechnical and Agronomical Analysesat AleksandrasStulginskis University. The experiment was carried out in 2012, the place of the experimentwas PetrasTikneviciusorganic farm located in Alytus region, Varena district, Geidukoniai village. The village is located in the South East part of Lithuania, in sandy uplands of Dainava region and plateau of Eisiskes. A two- factor experiment was carried out: the factor A was represented by the variety of Jerusalem artichoke, whereas the factor B indicated the development of the tubers during the cycle of ontogenesis (months). The samples were taken eight times: in March, April, May, June, August, September, October, and November. The following chemical structure of Jerusalem artichokes was determined through the application of standardized methods: the amount of dry matter, soluble dry matter, vitamin C, crude proteins, crude cellulose, crude ash, nitrates and potassium. Processing of the data of the analysis was carried out through the application of the method of Dispersive analysis; the minimum essential difference (R05) between two factors was calculated. Correlation dependency and the ratio of determination were calculated through the application of computer program Stateng. Averages and... [to full text]