Fructose has recently received much attention due to renewed interest in natural sweeteners. In addition, fructose has some advantages to sucrose in sweetness, solubility, viscosity, and dental health characteristics. Fructose is deposited as storage fructans of the inulin (beta-1,2) type in tubers and rhizomes of the Compositae family. The utilization of the Jerusalem artichoke (Helianthus tuberosus) tuber as a source of fructose syrup is discussed. This plant has the potential to produce more sugar per acre than corn or sugar beets. In addition, the artichoke has higher frost resistance and lower heat unit requirements than corn and is somewhat more tolerant to low moisture conditions than sugar beets. A high quality fructose syrup can be produced from artichoke tubers. The extraction step was found to be particularly important since development of adverse colors and flavors must be prevented. The fructans may be acid or enzyme hydrolyzed but the latter method gave a higher quality syrup. Ion-exchange resins and activated charcoal were effective in removing coloring and flavoring materials, and also reduced other noncarbohydrate constituents. Since the enzymatic hydrolysis of the fructans is an attractive alternative to acid hydrolysis, a process was developed for producing and purifying a special beta-fructofuranosidase (inulase) from Saccharomyces fragilis. Inulase has a much higher specificity for fructans than commerically available beta-fructofuranosidase (invertase).

Inulase production by Kluyveromyces fragilis on various fermentable and non-fermentable carbon sources was examined in carbon-limited continuous culture. Fructose and sucrose supported superior inulase yields [above 24 pmol sucrose hydrolysed min-l (mg cell dry wt)-l at pH 5.0, 50 "C], while some other carbon sources, including lactose, galactose, ethanol and lactate, did not stimulate inulase formation beyond basal levels. Thus fructose was identified as the primary physiological inducer. Isolation of a constitutive mutant also provided genetic evidence for the inducible nature of inulase in the wild-type. The mutant was generated spontaneously and selected in continuous culture. It produced high inulase activities in continuous culture irrespective of the carbon source. Inulase formation in the wild-type and mutant strain was further controlled by general carbon catabolite repression as suggested by enzyme yield patterns in batch and continuous culture.

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J. 1992. The effect of organic acids and enzyme supplementation on the performance of pigs fed barley-based diets. Can. J. Anim. Sci. 72: 395-402. Two factorial design experiments (sex X treatment) were conducted to determine the efficacy of enzyme and organic acid supplementation on improving the nutritive value ofbarley-based diets for both starter and finisher pigs. for exp. 1, 48 crossbred growing pigs (25.1 + 2.8 kg) were fed either a barleybased controi diet or a similar diet supplemented wtth0.25% enzyme (AspergiLlus nlger; 750 units g I beta-glucanase),2.5% propionic acid or a combination of these additives during a 77-d feeding irial. Forixp. 2, 120 cross6red weaner pigs (8.1 + 1.3 kg) were fed a hulless barley-based control diet or a similar diet supplemented with 0.25% enzyme (Aspergillus niger; 150 units g ' betaglucanase), 2.0% fumar\c icid or both additives in combination for a 35-d feeding period. In exp. 1, iupplementation with either enzyme or propionic acid alone, significantly (P<0.05) increased dry matter digestibility. However, when ihe additives were fed in combination, the digestibility coefficient for dr-y matter was not significantly different from the control. Digestibility coefficients for crude protein und .n.rgy were not;ffected by any treatment. Growth rate, feed intake, feed efficiency and carcass traits weie also not improved by supplementation with enzyme or propionic acid, either when fed alone or in combinarion. ln exp. 2. digesribiliry coefficients for dry matter. crude protein antJ energy were not affected by enzyme or acid treatment. In addition, there were no differences in growth, feed intake or feed efficiency is a result of any treatment. Supplementation with organic acids would therefbre appear to be ineffective in potentiating the response to dietary beta-glucanase in pigs fed barley-based diets.

Frost‐damaged or prematurely harvested canola seed (rapeseed) may yield oil with a high chlorophyll content (50–60 µg/ml). Enzymatic hydrolysis of chlorophyll, added to buffer/surfactant, buffer/acetone or buffer/acetone/canola oil, to produce water‐soluble chlorophyllide (green pigment) was studied using a crude chlorophyllase preparation (acetone‐dried chloroplasts) from 15 to 20‐day‐old sugar beet seedlings. In buffer/surfactant, the optimum pH for enzyme activity was temperature dependent. At 30 C and 0.24% Triton X‐100 (or 30% acetone), chlorophyllase showed maximum activity toward a crude chlorophyll preparation over the range of pH 8–10. At 60 C, the activity was more than twofold higher, with a sharp maximum at ∼pH 8. Mg2+ enhanced the activity with an optimal concentration of 50 mM. At pH 7.5, 50 C and in the presence of only 6% acetone, the enzyme showed high affinity for chlorophyll (Km=15µM or 13.5 µg/ml), suggesting that the natural chlorophyll concentrations found in green canola oils might facilitate high enzymatic efficiencies. The crude enzyme was stable in buffer/acetone at pH 7.5 and 50 C for at least two hr.With acetone concentrations as low as 6%, maximum enzyme activities in buffer and buffer/canola oil required intensive mixing (homogenization) of the various substrate, enzyme and liquid phases. In general, the rate and extent of chlorophyll hydrolysis were greater in buffer than in buffer/oil. In both reaction systems, chlorophyll hydrolysis slowed down with time due to accumulation of phytol, which proved to be a competitive inhibitor (Ki=11 µM or 3.3 µg/ml). The other hydrolysis product, chlorophyllide, did not affect enzymatic activity.Crude canola oil used in the reconstitution of green oil did not support enzymatic chlorophyll hydrolysis without prior degumming and desoaping. The optimum buffer/oil ratio of the reaction mixtures was above 2/1 (v/v).

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A total of 138 crossbred pigs were fed either a barley-based control diet or a rye-based diet supplemented or unsupplemented with a crude enzyme preparation with pentosanase activity. Digestibility coefficients were generally higher (P < 0.05) for pigs fed rye-based diets in comparison with barley while enzyme supplementation had no effect on nutrient digestibility. When fed in a meal form, there was a significant reduction (P < 0.05) in the growth rate of pigs fed rye-based diets compared with barley (exp. 1). However, no significant differences were observed when pelleted diets were fed (exp. 2). The results of both experiments indicate that rye-based diets are not consumed as readily as barley-based diets although pigs fed rye-based diets had improved feed efficiencies. Supplementation with pentosanase did not significantly improve pig performance although in both experiments, there was a trend towards an improvement in growth rate. In exp. 1, there were no significant differences (P > 0.05) in slaughter weight, carcass weight, dressing percentage, estimated lean yield or carcass value index as a result of differences in the cereal base of the diet or enzyme supplementation. In exp. 2, the carcass weight and dressing percentage of pigs fed the rye-based diets were lower than those of the control (P < 0.05). In conclusion, it would appear that soluble pentosans do not pose as large a problem for swine as they do for poultry. Key words: Swine, rye, pentosans, pentosanase, digestibility

Preparing homogeneous UDP-g1ucose:thiohydroximate S-glucosyltransferase (S-CT), the penultimate biosynthetic enzyme of glucosinolates, by standard chromatographic methods has yielded too little protein for adequate purity evaluation, identity verification, and structural analysis. l h e low yields were apparently due to low abundance in source tissues, aggravated by enzyme instability. Here we describe an immunological method for purification of-workable quantities from florets of Brassica oleracea ssp. botrytis (cauliflower). Florets that had undergone browning dueto exposure to sunlight contained higher S-CT activities than are normally found in Brassica tissues. S-CT was adsorbed from crude tissue extracts onto an agarose-monoclonal antibody complex. Elution from the complex required harsh alkaline conditions (pH 11.51, giving extremely variable activity recoveries (maximum 20%). l h e eluate contained two proteins that could be separated readily by preparative polyacrylamide gel electrophoresis or anion-exchange chromatography. The overall S-CT protein recovery was estimated at less than 200 pg/kg of cauliflower tissue. Molecular weight determinations with homogeneous cauliflower S-CT gave relative molecular weight (M,) values of 55,500 as estimated by sodium dodecyl sulfate-polyacrylamide gel electrophoresis and 57,600 by gel chromatography; isoenzymes with isoelectric point values of 4.80 and 4.95 were identified. A polyclonal antibody raised against denatured enzyme showed broad cross-reactivity in immunoblots with S-CT from a number of Brassica species and other crucifers. l h e monoclonal antibody that was used in the immunopurification was much more specific; it exclusively precipitated S-CT isoenzymes that had their genomic origin in the primary diploids B. oleracea and Brassica campestris. Thus, all of the S-CT was precipitated from the amphidiploid Brassica napus, which is a hybrid of B. oleracea and B. campestris. About half of the S-CT was precipitated from the amphidiploids Brassica carinata and Brassica juncea, which have B. oleracea and B. campestris as one of their parents, respectively. It was shown that the S-CT isoenzymes of B. juncea with M, 55,500 and about 57,000 originate from the parents B. campestris and B. nigra, respectively.GS (sulfated S-glucosyl thiohydroximates) constitute a large group of secondary metabolites occurring in severa1 plant families, including a11 species of the Cruciferae. Their presence in oilseed Brassica crops (Brassica napus and Brassica campestris) has been of great nutritional and therefore economic concern, since the meal fraction is directed to animal feed markets as a protein source. GS have antinutritional properties and cause acute and chronic diseases, particularly * Corresponding author; fax 1-306-975-4839. 425