Mixture Of Maltose Research Articles

The radiation assisted-Maillard reaction comprehensively improves the freeze-thaw stability of soy protein-stabilized oil-in-water emulsions

For the first time, the irradiation technology combined with Maillard reaction were used to improve the freeze - thaw stability of soybean protein emulsion. The freeze-thaw stability of emulsions prepared with soy protein isolate (SPI), soy protein isolate and maltose mixture (SPI + M) or glycosylated soy protein isolate with maltose formed by irradiation of 7.5 kGy and 12.5 kGy (named SPI-M7.5 and SPI-M12.5, respectively) was compared. Fourier transform infrared spectroscopy, fluorescence spectroscopy and ultraviolet spectroscopy confirmed the change of the structure of soy protein isolate, indicating that maltose was covalently linked to soybean protein isolate. Scanning electron microscopy showed that the modified protein particles were more loose, uniform in size, and significantly reduced in molecular aggregation than untreated protein. The freeze-thaw stability of SPI, SPI + M, and SPI-M7.5 and SPI-M12.5 emulsions was evaluated. It was found that after three freeze-thaw cycles, the creaming index, oiling off, particle size, coalescence degree and flocculation degree of emulsions prepared with irradiated SPI samples were all lower than those prepared with SPI and SPI + M. Zeta potential, laser confocal and optical microscopy showed that the emulsion was still in a relatively stable state, and the SPI-M7.5 emulsion after freeze-thaw treatment was more stable than the SPI-M12.5 emulsion.

Water sorption, glass transition, and freeze-concentrated glass-like transition properties of calcium maltobionate–maltose mixtures

The water sorption, glass transition, and freeze-concentrated thermal transition properties of calcium maltobionate (MBCa)–maltose mixtures were investigated. At lower maltose molar fractions, the water content of the mixtures increased sigmoidally with water activity (aw). At higher maltose molar fractions, maltose preferentially crystallized in an aw condition, and water sorption isotherms deviated from sigmoidal behavior. The glass transition temperature (Tg) decreased with increasing water content because of a water-plasticizing effect, described as a Tg curve. The critical water content (Wc) and critical water activity (awc) (i.e., water content and aw at Tg = 298 K) were determined from the water sorption isotherms and Tg curves. The values of Wc and awc decreased linearly with increasing maltose molar fraction. The DSC curve of the MBCa–maltose aqueous solutions showed a large endothermic shift before the endothermic peak due to melting ice, and freeze-concentrated glass-like transition temperature (Tg′) was evaluated from the endothermic shift. The Tg′ of the MBCa–maltose aqueous solutions decreased with increasing maltose molar fraction. These results are useful for predicting the physical stability (collapse, crystallization of maltose, and powder caking) of MBCa–maltose mixtures during freeze-drying and subsequent storage.

Structure and function of the type III pullulan hydrolase from Thermococcus kodakarensis.

Pullulan-hydrolysing enzymes, more commonly known as debranching enzymes for starch and other polysaccharides, are of great interest and have been widely used in the starch-saccharification industry. Type III pullulan hydrolase from Thermococcus kodakarensis (TK-PUL) possesses both pullulanase and α-amylase activities. Until now, only two enzymes in this class, which are capable of hydrolysing both α-1,4- and α-1,6-glycosidic bonds in pullulan to produce a mixture of maltose, panose and maltotriose, have been described. TK-PUL shows highest activity in the temperature range 95-100°C and has a pH optimum in the range 3.5-4.2. Its unique ability to hydrolyse maltotriose into maltose and glucose has not been reported for other homologous enzymes. The crystal structure of TK-PUL has been determined at a resolution of 2.8 Å and represents the first analysis of a type III pullulan hydrolyse. The structure reveals that the last part of the N-terminal domain and the C-terminal domain are significantly different from homologous structures. In addition, the loop regions at the active-site end of the central catalytic domain are quite different. The enzyme has a well defined calcium-binding site and possesses a rare vicinal disulfide bridge. The thermostability of TK-PUL and its homologues may be attributable to several factors, including the increased content of salt bridges, helical segments, Pro, Arg and Tyr residues and the decreased content of serine.

Chitinase activity of Pseudomonas stutzeri PT5 in different fermentation condition

This study aimed to determine the incubation condition of Pseudomonas stutzeri PT5 in producing chitin degrading enzyme in various pH and temperatures; to compare the production of chitin degrading enzyme in chitin medium supplemented with additional nitrogen, carbon and a mixture of nitrogen and carbon sources and to observe the production of chitin degrading enzyme in 250 mL-shake flasks and 2 L-fermentor. The parameters tested during production were chitinase activity (U·mL-1) of culture supernatant and N-acetylglucosamine concentration (μg·mL-1) in the medium. The results showed that Pseudomonas stutzeri PT5 was able to produce the highest chitinase activity at pH 6 and temperature of 37 °C (0.024 U·mL-1). The addition of 0.1 % of ammonium phosphate and 0.1 % of maltose, increased the chitinase activity of Pseudomonas stutzeri PT5 by 3.24 and 8.08 folds, respectively, compared to the control. The addition of 0.1 % ammonium phosphate and 0.1 % maltose mixture to chitin medium resulted in the shorter time of chitinase production compared to the addition of sole nutrition. The production of chitinase using 2 L-fermentor shows that the highest chitinase activity produced by Pseudomonas stutzeri PT5 was reached at 1-day incubation (0.0283 U·mL-1), which was shorter than in 250 mL-shake flasks.

Synthesis of Isomaltooligosaccharides by Saccharomyces cerevisiae Cells Expressing Aspergillus niger α-Glucosidase

The α-glucosidase encoded by the aglA gene of Aspergillus niger is a secreted enzyme belonging to family 31 of glycoside hydrolases. This enzyme has a retaining mechanism of action and displays transglycosylating activity that makes it amenable to be used for the synthesis of isomaltooligosaccharides (IMOs). We have expressed the aglA gene in Saccharomyces cerevisiae under control of a galactose-inducible promoter. Recombinant yeast cells expressing the aglA gene produced extracellular α-glucosidase activity about half of which appeared cell bound whereas the other half was released into the culture medium. With maltose as the substrate, panose is the main transglycosylation product after 8 h of incubation, whereas isomaltose is predominant after 24 h. Isomaltose also becomes predominant at shorter times if a mixture of maltose and glucose is used instead of maltose. To facilitate IMO production, we have designed a procedure by which yeast cells can be used directly as the catalytic agent. For this purpose, we expressed in S. cerevisiae gene constructs in which the aglA gene is fused to glycosylphosphatidylinositol anchor sequences, from the yeast SED1 gene, that determine the covalent binding of the hybrid protein to the cell membrane. The resulting hybrid enzymes were stably attached to the cell surface. The cells from cultures of recombinant yeast strains expressing aglA-SED1 constructions can be used to produce IMOs in successive batches.

Production of 5-O-α-glucosylgingerol via glucosylation of 6-gingerol by Ensifer sp. M-26

6-Gingerol ((S)-5-hydroxy-1-(4-hydroxy-3-methoxyphenyl)-3-decanone), the major gingerol present in ginger rhizomes, has been found to prevent fat accumulation and improve blood flow. However, its low solubility in water and strong pungent odor often limit its potential applications such as in functional foods. In order to overcome these disadvantages, we investigated microbial glucosylation of 6-gingerol by the soil bacterium Ensifer sp. M-26. 5-O-α-Glucosylgingerol was found to be produced from a mixture of maltose and 6-gingerol by the action of washed cells of Ensifer sp. M-26. The addition of organic solvents, such as hexane, to the reaction mixture enhanced 5-O-α-glucosylgingerol production. When the microbial reaction was carried out with 1.3g/L of 6-gingerol and 100g/L of maltose under optimized conditions, 0.40g/L of 5-O-α-glucosylgingerol was accumulated in 25h. The molar yield of 5-O-α-glucosylgingerol was 19.9mol%.

Deteriorated glucose metabolism with a high-protein, low-carbohydrate diet in db mice, an animal model of type 2 diabetes, might be caused by insufficient insulin secretion.

We previously showed the deleterious effects of increased dietary protein on renal manifestations and glucose metabolism in leptin receptor-deficient (db) mice. Here, we further examined its effects on glucose metabolism, including urinary C-peptide. We also orally administered mixtures corresponding to low- or high-protein diets to diabetic mice. In diet experiments, under pair-feeding (equivalent energy and fat) conditions using a metabolic cage, mice were fed diets with different protein content (L diet: 12% protein, 71% carbohydrate, 17% fat; H diet: 24% protein, 59% carbohydrate, 17% fat) for 15days. In oral administration experiments, the respective mixtures (L mixture: 12% proline, 71% maltose or starch, 17% linoleic acid; H mixture: 24% proline, 59% maltose or starch, 17% linoleic acid) were supplied to mice. Biochemical parameters related to glucose metabolism were measured. The db-H diet mice showed significantly higher water intake, urinary volume, and glucose levels than db-L diet mice but similar levels of excreted urinary C-peptide. In contrast, control-H diet mice showed significantly higher C-peptide excretion than control-L diet mice. Both types of mice fed H diet excreted high levels of urinary albumin. When maltose mixtures were administered, db-L mixture mice showed significantly higher blood glucose after 30min than db-H mixture mice. However, db mice administered starch-H mixture showed significantly higher blood glucose 120-300min post-administration than db-L mixture mice, although both groups exhibited similar insulin levels. High-protein, low-carbohydrate diets deteriorated diabetic conditions and were associated with insufficient insulin secretion in db mice. Our findings may have implications for dietary management of diabetic symptoms in human patients.

Enzymatic Formation of Novel Ginsenoside Rg1-α-Glucosides by Rat Intestinal Homogenates.

The variation of linkage positions in ginsenosides leads to diverse pharmacological efficiencies. The hydrolysis and transglycosylation properties of glycosyl hydrolase family enzymes have a great impact on the synthesis of novel and structurally diversified compounds. In this study, six ginsenoside Rg1-α-glucosides were found to be synthesized from the reaction mixture of maltose as a donor and ginsenoside Rg1 as a sugar acceptor in the presence of rat small intestinal homogenates, which exhibit high α-glucosidase activities. The individual compounds were purified and were identified by spectroscopy (HPLC-MS, (1)H-NMR, and (13)C-NMR) as 6-O-[α-D-glcp-(1→4)-β-D-glcp]-20-O-(β-D-glcp)-20(S)-protopanaxatriol, 6-O-β-D-glcp-20-O-[α-D-glcp-(1→6)-(β-D-glcp)]-20(S)-protopanaxatriol, 6-O-β-D-glcp-20-O-[α-D-glcp-(1→4)-(β-D-glcp)]-20(S)-protopanaxatriol, 6-O-[α-D-glcp-(1→6)-β-D-glcp]-20-O-(β-glcp)-20(S)-protopanaxatriol, 6-O-[α-D-glcp-(1→3)-β-D-glcp]-20-O-(β-D-glcp)-20(S)-protopanaxatriol, and 6-O-β-D-glcp-20-O-[α-D-glcp-(1→3)-(β-D-glcp)]-20(S)-protopanaxatriol. Among these six, 6-O-β-D-glcp-20-O-α-D-glcp-(1→6)-(β-D-glcp)-20(S)-protopanaxatriol and 6-O-α-D-glcp-(1→6)-β-D-glcp-20-O-(β-D-glcp)-20(S)-protopanaxatriol are considered to be novel compounds of alpha-ginsenosidal saponins which pharmacological activities should be further characterized. This is the first report on the enzymatic elaboration of ginsenoside Rg1 derivatives using rat intestinal homogenates. To the best of our knowledge, it is also the first to reveal the sixth and 20th positions of an unusual α-D-glucopyranosyl-(1→6)-β-D-glucopyranosyl sugar chain with 20(S)-protopanaxatriol saponins in Panax ginseng Mayer.

Degradation of disaccharides containing two glucose units in subcritical water

AbstractDisaccharides containing two glucose units, including trehalose, cellobiose, maltose, gentiobiose, and isomaltose, were hydrolyzed in a single‐component system using subcritical water at 200–240 °C and 10 MPa. A mixture of maltose and trehalose was also hydrolyzed in a binary‐component system using subcritical water at 210 and 230 °C. The fraction of the remaining disaccharides decreased as a function of the residence time and could be expressed by the Weilbull equation at any temperature. While trehalose showed the highest resistance to hydrolysis, the other disaccharides were much less resistant to hydrolysis and their reaction rates were not much different from each other. The mixture of trehalose and maltose exhibited a reduced resistance to the hydrolysis of trehalose at high hydrolysis temperatures. In addition, glucose, which was the product of the hydrolysis, can be easily subjected to further degradation to organic acids and consequently reduces the pH of the effluent. © 2015 Curtin University of Technology and John Wiley & Sons, Ltd.

Effect of introducing a disulphide bond between the A and C domains on the activity and stability of Saccharomycopsis fibuligera R64 α-amylase

Native enzyme and a mutant containing an extra disulphide bridge of recombinant Saccharomycopsis fibuligera R64 α-amylase, designated as Sfamy01 and Sfamy02, respectively, have successfully been overexpressed in the yeast Pichia pastoris KM71H. The purified α-amylase variants demonstrated starch hydrolysis resulting in a mixture of maltose, maltotriose, and glucose, similar to the wild type enzyme. Introduction of the disulphide bridge shifted the melting temperature (TM) from 54.5 to 56°C and nearly tripled the enzyme half-life time at 65°C. The two variants have similar kcat/KM values. Similarly, inhibition by acarbose was only slightly affected, with the IC50 of Sfamy02 for acarbose being 40±3.4μM, while that of Sfamy01 was 31±3.9μM. On the other hand, the IC50 of Sfamy02 for EDTA was 0.45mM, nearly two times lower than that of Sfamy01 at 0.77mM. These results show that the introduction of a disulphide bridge had little effect on the enzyme activity, but made the enzyme more susceptible to calcium ion extraction. Altogether, the new disulphide bridge improved the enzyme stability without affecting its activity, although minor changes in the active site environment cannot be excluded.

ChemInform Abstract: Catalyst‐Free Synthesis of Quinazoline Derivatives Using Low Melting Sugar—Urea—Salt Mixture as a Solvent.

Low melting mixture of maltose–dimethylurea (DMU)–NH4Cl was found to be an inexpensive, non-toxic, easily biodegradable and effective reaction medium in the catalyst-free synthesis of quinazoline derivatives. This simple and efficient method furnished the corresponding quinazolines in high yields via one-pot three-component reaction of 2-aminoaryl ketones, aldehyde, and ammonium acetate under aerobic oxidation conditions.

Characteristics and antioxidant activities of ovalbumin glycated with different saccharides under heat moisture treatment

Ovalbumin (OVA) was glycosylated with glucose, lactose, maltose and soluble starch respectively under heat moisture treatment at 120°C for 20min. The UV–vis absorbance and browning intensity, free amino group, thermal properties, tertiary structure and antioxidant activities were investigated. The results indicated that the OVA–glucose and OVA–maltose mixture exhibited stronger browning intensity as well as reducing power and DPPH scavenging activity than other samples. The OVA–lactose and OVA–glucose displayed higher TEAC value, up to 1.92±0.11 and 1.96±0.14mmolTrolox/g, respectively. The Maillard reaction involving the condensation of reducing sugar and protein modified the thermal stability of ovalbumin. The tertiary structure of OVA was significantly influenced by the Maillard reaction. The antioxidant activity of the Maillard reaction products prepared in such a short time was so strong, suggesting that generation of in vitro liquid Maillard products is a potential source of external antioxidants for food preservation.

Catalyst-free synthesis of quinazoline derivatives using low melting sugar–urea–salt mixture as a solvent

Low melting mixture of maltose–dimethylurea (DMU)–NH4Cl was found to be an inexpensive, non-toxic, easily biodegradable and effective reaction medium in the catalyst-free synthesis of quinazoline derivatives. This simple and efficient method furnished the corresponding quinazolines in high yields via one-pot three-component reaction of 2-aminoaryl ketones, aldehyde, and ammonium acetate under aerobic oxidation conditions.

Cryoprotection–lyophilization and physical stabilization of rifampicin-loaded flower-like polymeric micelles

Rifampicin-loaded poly(ε-caprolactone)-b-poly(ethylene glycol)-poly(ε-caprolactone) flower-like polymeric micelles display low aqueous physical stability over time and undergo substantial secondary aggregation. To improve their physical stability, the lyoprotection-lyophilization process was thoroughly characterized. The preliminary cryoprotectant performance of mono- and disaccharides (e.g. maltose, glucose), hydroxypropyl-β-cyclodextrin (HPβCD) and poly(ethylene glycol) (PEG) of different molecular weights was assessed in freeze-thawing assays at -20°C, -80°C and -196°C. The size and size distribution of the micelles at the different stages were measured by dynamic light scattering (DLS). A cryoprotectant factor (f(c)) was determined by taking the ratio between the size immediately after the addition of the cryoprotectant and the size after the preliminary freeze-thawing assay. The benefit of a synergistic cryoprotection by means of saccharide/PEG mixtures was also assessed. Glucose (1 : 20), maltose (1 : 20), HPβCD (1 : 5) and glucose or maltose mixtures with PEG3350 (1 : 20) (copolymer:cryoprotectant weight ratio) were the most effective systems to protect 1 per cent micellar systems. Conversely, only HPβCD (1 : 5) cryoprotected more concentrated drug-loaded micelles (4% and 6%). Then, those micelle/cryoprotectant systems that displayed f(c) values smaller than 2 were freeze-dried. The morphology of freeze-dried powders was characterized by scanning electron microscopy and atomic force microscopy and the residual water content analysed by the Karl Fisher method. The HPβCD-added lyophilisates were brittle porous cakes (residual water was between 0.8% and 3%), easily redispersable in water to form transparent systems with a minimal increase in the micellar size, as determined by DLS.

PURIFICATION AND CHARACTERIZATION OF PULLULANASE FROM Lactococcus lactis

This paper describes a simple and efficient method of isolation of a plullulanase type I from amylolytic lactic acid bacteria (ALAB). Extracellular pullulanase type I was purified from a cell-free culture supernatant of Lactococcus lactis IBB 500 by using ammonium sulfate fractionation and dialysis (instead of ultrafiltration), and ion-exchange chromatography with CM Sepharose FF followed by gel filtration chromatography with Sephadex G-150 as the final step. A final purification factor of 14.36 was achieved. The molecular mass of the enzyme was estimated as 73.9 kD. The optimum temperature for the enzyme activity was 45°C and the optimum pH was 4.5. Pullulanase activity was increased by addition Co2+ and completely inhibited by Hg2+. The enzyme activity was specifically directed toward α-1,6 glycosidic linkages of pullulan giving maltotriose units. Enzymatic hydrolysis of starch and amylose produced a mixture of maltose and maltotriose.

Characteristics of raw starch degrading α‐amylase from Bacillus aquimaris MKSC 6.2 associated with soft coral Sinularia sp.

AbstractPartially purified α‐amylase from Bacillus aquimaris MKSC 6.2, a bacterium isolated from a soft coral Sinularia sp., Merak Kecil Island, West Java, Indonesia, showed an ability to degrade raw corn, rice, sago, cassava, and potato starches with adsorption percentage in the range of 65–93%. Corn has the highest degree of hydrolysis followed by cassaca, sago potato and rice, consecutively. The end products of starch hydrolysis were a mixture of maltose, maltotriose, maltotetraose, maltopentaose, maltohexaose, and small amount of glucose.

Interference Studies with Two Hospital-Grade and Two Home-Grade Glucose Meters

Interference studies of four glucose meters (Nova Biomedical [Waltham, MA] StatStrip [hospital grade], Roche Diagnostics [Indianapolis, IN] Accu-Chek Aviva [home grade], Abbott Diabetes Care [Alameda, CA] Precision FreeStyle Freedom [home grade], and LifeScan [Milpitas, CA] SureStep Flexx [hospital grade]) were evaluated and compared to the clinical laboratory plasma hexokinase reference method (Roche Hitachi 912 chemistry analyzer). These meters were chosen to reflect the continuum of care from hospital to home grade meters commonly seen in North America. Within-run precision was determined using a freshly prepared whole blood sample spiked with concentrated glucose to give three glucose concentrations. Day-to-day precision was evaluated using aqueous control materials supplied by each vendor. Common interferences, including hematocrit, maltose, and ascorbate, were tested alone and in combination with one another on each of the four glucose testing devices at three blood glucose concentrations. Within-run precision for all glucose meters was <5% except for the FreeStyle (up to 7.6%). Between-day precision was <6% for all glucose meters. Ascorbate caused differences (percentage change from a sample without added interfering substances) of >5% with pyrroloquinolinequinone (PQQ)-glucose dehydrogenase-based technologies (Aviva and Freestyle) and the glucose oxidase-based Flexx meter. Maltose strongly affected the PQQ-glucose dehydrogenase-based meter systems. When combinations of interferences (ascorbate, maltose, and hematocrit mixtures) were tested, the extent of the interference was up to 193% (Aviva), 179% (FreeStyle), 25.1% (Flexx), and 5.9% (StatStrip). The interference was most pronounced at low glucose (3.9-4.4 mmol/L). All evaluated glucose meter systems demonstrated varying degrees of interference by hematocrit, ascorbate, and maltose mixtures. PQQ-glucose dehydrogenase-based technologies showed greater susceptibility than glucose oxidase-based systems. However, the modified glucose oxidase-based amperometric method (Nova StatStrip) was less affected in comparison with the glucose oxidase-based photometric method (LifeScan SureStep Flexx).

Characterization of Pullulanase Type II from Bacillus cereus H1.5

Problem statement: Pullulanase is one of the important enzymes in starch industry. Search for the pullulanase with distinct features, possibly from easily grown bacterium, is of interest for industrial applications Approach: The extracellular pullulanase produced by Bacillus cereus HI.5 was purified by chromatographic method of DEAE-Sepharose, followed by Superdex gel filtration. The enzyme was characterized in terms of the optimal pH and temperature for activity as well as substrate specificity. Results: The enzyme showed optimal activity at 55°C and pH 6.0. The thermostability and the thermoactivity of the enzyme were increased considerably in the presence of Ca2+. In the present of 2 mM Ca2+, the enzyme had half-life duration of more than 2 h at 50°C. Almost all metal ions had a strong inhibitory effect, except Ca2+ and Mn2+. The Ca2+ had a very strong stimulating effect on the enzyme, increasing its activity by 170%. The enzyme was activated by 2-mercaptoethanol and dithiothreitol, where as N-bromosuccinimide and Schardinger dextrins were inhibitors, suggesting that tryptophan and thiol residues may be important for the activity. The apparent Km and Vmax value for pullulan was 1.1 mg mL-1 and 0.275 μmol min-1, respectively. A relative substrate specificity for hydrolysis of pullulan, amylopectin and soluble starch by this pullulanase was 100%, 28.5% and 20.4%, respectively. Conclusion: The enzyme was able to attack specifically the α-1,6 linkages in pullulan to generate maltotriose as the major end product, as well as the α-1,4 linkages in amylopectin and soluble starch leading to the formation of a mixture of maltose and glucose and therefore be classified as a type II pullulanase or an amylopullulanase.

Transglucosylation activities of multiple forms of alpha-glucosidase from spinach.

Transglucosylation activities of spinach alpha-glucosidase I and IV, which have different substrate specificity for hydrolyzing activity, were investigated. In a maltose mixture, alpha-glucosidase I, which has high activity toward not only maltooligosaccharides but also soluble starch and can hydrolyze isomaltose, produced maltotriose, isomaltose, and panose, and alpha-glucosidase IV, which has high activity toward maltooligosaccharides but faint activity toward soluble starch and isomaltose, produced maltotriose, kojibiose, and 2,4-di-alpha-D-glucosyl-glucose. Transglucosylation to sucrose by alpha-glucosidase I and IV resulted in the production of theanderose and erlose, respectively, showing that spinach alpha-glucosidase I and IV are useful to synthesize the alpha-1,6-glucosylated and alpha-1,2- and 1,4-glucosylated products, respectively.

Different food sources affect the gustatory response of Anaphes iole, an egg parasitoid of Lygus Spp.

The gustatory response of female Anaphes iole wasps to naturally occurring carbohydrates, a commercial food source, and host (Lygus lineolaris) frass was determined. Wasps responded to all 14 of the sugars at the highest concentration tested (2 M). At this concentration, sucrose, glucose, maltose, melezitose, fructose, and erlose all elicited > 90% acceptance. The lowest concentration that evoked a response (= acceptance threshold) for these sugars was < 1/256 M, with the exception of glucose. which was 1/16 M. Raffinose, trehalose, mannose, galactose, melibiose, rhamnose, stachyose, and lactose led to < 50% gustatory response by the wasps at 2 M, and were categorized as "moderately stimulatory sugars." The acceptance threshold for these sugars was > 1/4 M, with the exception of raffinose, which was 1/256 M. In trials with moderately stimulatory sugars combined with either sucrose or maltose, only the rhamnose+maltose mixture significantly inhibited the gustatory response of A. iole. Food and water deprived parasitoids readily accepted the moderately stimulatory sugars. Eliminade, a commercial food supplement, was readily accepted (92%) by A. iole. Conversely, the wasps did not feed on host frass. Chemical analysis of L. lineolaris frass demonstrated the presence of glucose, sucrose, fructose, trehalulose, and melezitose, apparently at concentrations below those perceived by A. iole. The latter two compounds were previously known only from homopteran honeydew (trehalulose and melezitose) and bacteria (trehalulose). With respect to gustatory response to nectar and honeydew sugars, A. iole differs markedly from other hymenopterans that have been studied in that this parsitoid accepted all the naturally occurring sugars with which it was tested. Moreover, this parasitoid had lower acceptance thresholds than other hymenopterans for many of the sugars. This broad and sensitive range of gustatory perception might be helpful in the development of a food source for the wasp that is not exploited by the host.