Addition Of Α-amylase Research Articles

Sensitive detection of α-amylase based on host–guest inclusion system of γ-cyclodextrin and dansyl-derived diphenylalanine

A highly sensitive detection system for α-amylase was developed via host–guest complexation between γ-cyclodextrin and dansyl-modified diphenylalanine (FF-Dns). The host–guest inclusion of FF-Dns into the cavity of γ-CD in a HEPES buffer solution (10 mM, pH 7.4) significantly enhanced the fluorescence intensity, and the emission wavelength gradually shifted from 558 to 535 nm. The hydrolysis of γ-CD by the addition of α-amylase released FF-Dns, leading to the recovery of the fluorescence emission characteristics. Therefore, the FF-Dns/γ-CD host–guest complexation system can serve as a platform for the sensitive detection of α-amylase with good selectivity against potential interference. The limit of detection (LOD) of the system was 0.004 U/mL, with a linear working range of 0–6 U/mL. The detection assay was successfully applied in 0.1 % serum, achieving an LOD of 0.017 U/mL and a linear working range of 0–10 U/mL.

Construction of an amylolytic Saccharomyces cerevisiae strain with high copies of α-amylase and glucoamylase genes integration for bioethanol production from sweet potato residue.

Sweet potato residue (SPR) is the by-product of starch extraction from fresh sweet potatoes and is rich in carbohydrates, making it a suitable substrate for bioethanol production. An amylolytic industrial yeast strain with co-expressing α-amylase and glucoamylase genes would combine enzyme production, SPR hydrolysis, and glucose fermentation into a one-step process. This consolidated bioprocessing (CBP) shows great application potential in the economic production of bioethanol. In this study, a convenient heterologous gene integration method was developed. Eight copies of a Talaromyces emersonii α-amylase expression cassette and eight copies of a Saccharomycopsis fibuligera glucoamylase expression cassette were integrated into the genome of industrial diploid Saccharomyces cerevisiae strain 1974. The resulting recombinant strains exhibited clear transparent zones in the iodine starch plates, and SDS-PAGE analysis indicated that α-amylase and glucoamylase were secreted into the culture medium. Enzymatic activity analysis demonstrated that the optimal temperature for α-amylase and glucoamylase was 60-70°C, and the pH optima for α-amylase and glucoamylase was 4.0 and 5.0, respectively. Initially, soluble corn starch with a concentration of 100 g/L was initially used to evaluate the ethanol production capability of recombinant amylolytic S. cerevisiae strains. After 7 days of CBP fermentation, the α-amylase-expressing strain 1974-temA and the glucoamylase-expressing strain 1974-GA produced 33.03 and 28.37 g/L ethanol, respectively. However, the 1974-GA-temA strain, which expressed α-amylase and glucoamylase, produced 42.22 g/L ethanol, corresponding to 70.59% of the theoretical yield. Subsequently, fermentation was conducted using the amylolytic strain 1974-GA-temA without the addition of exogenous α-amylase and glucoamylase, which resulted in the production of 32.15 g/L ethanol with an ethanol yield of 0.30 g/g. The addition of 20% glucoamylase (60 U/g SPR) increased ethanol concentration to 50.55 g/L, corresponding to a theoretical yield of 93.23%, which was comparable to the ethanol production observed with the addition of 100% α-amylase and glucoamylase. The recombinant amylolytic strains constructed in this study will facilitate the advancement of CBP fermentation of SPR for the production of bioethanol.

Proteomic Analysis of Differences in the Freezability of Porcine Sperm Identifies α-Amylase As a Key Protein.

To investigate the mechanisms underlying the differences in the freezability of boar semen, Yorkshire boars with freezing-tolerant semen (YT, n = 3), Yorkshire boars with freezing-sensitive semen (YS, n = 3), Landrace boars with freezing-tolerant semen (LT, n = 3), and Landrace boars with freezing-sensitive semen (LS, n = 3) were selected for this study. Their sperm was subjected to protein extraction, followed by data-independent acquisition proteomics and functional bioinformatics analysis. A total of 3042 proteins were identified, of which 2810 were quantified. Some key KEGG pathways were enriched, such as starch and sucrose metabolism, carbohydrate digestion and absorption, mineral absorption, the HIF-1 signaling pathway, and the necroptosis pathways. Through PRM verification, we found that several proteins, such as α-amylase and epididymal sperm-binding protein 1, can be used as molecular markers of the freezing resistance of boar semen. Furthermore, we found that the addition of α-amylase to cryoprotective extender could significantly improve the post-thaw motility and quality of boar semen. In summary, this study revealed some molecular markers and potential molecular pathways contributing to the high or low freezability of boar sperm, identifying α-amylase as a key protein. This study is valuable for optimizing boar semen cryopreservation technology.

In vitro gastric digestion of polysaccharides in mixed dispersions: Evaluating the contribution of human salivary α-amylase on starch molecular breakdown

The aim of this work was to investigate the impact of the addition of salivary α-amylase on starch hydrolysis in protein-containing dispersions during an in vitro digestion process. In vitro digestion provides useful insights on the fate of nutrients during gastro-intestinal transit in complex food matrices, an important aspect to consider when developing highly nutritious foods. Many foods contain polysaccharides, and as their disruption in the gastric stage is limited, salivary α-amylase is often neglected in in vitro studies. A reference study on the effect of salivary α-amylase using one of the most advanced and complex in vitro digestion models (INFOGEST) is, however, not available. Hence, this work reports the gastrointestinal breakdown of three mixed dispersions containing whey protein isolate with different polysaccharides: potato starch, pectin from citrus peel and maize starch. The latter was also studied after heating. No polysaccharide or salivary α-amylase-dependent effect on protein digestion was found, based on the free NH2 and SDS-PAGE. However, in the heat-treated samples, the addition of salivary α-amylase showed a significantly higher starch hydrolysis compared to the sample without α-amylase, due to the gelatinization of the starch granules, which improved the accessibility of the starch molecules to the enzyme. This work demonstrated that the presence of different types of polysaccharides does not affect protein digestion, but also it emphasizes the importance of considering the influence of processing on food structure and its digestibility, even in the simplest model systems.

Pretreatment process of rice syrup production and analysis of physicochemical properties

ABSTRACT A pretreatment experiment of preparing starch syrup with α-amylase and twin-screw extrusion together with broken rice of resistant starch rice was studied. Results showed that the content of reducing sugar in the extrudate was 23.52% when the moisture content of the material was 25%, the screw speed was 210 r/min, the barrel temperature was 85°C, and the addition amount of α-amylase was 90 U/g. The influence of various factors was ranked as follows: material ratio > screw speed > α-amylase addition > barrel temperature. After the extrusion, the contents of starch and resistant starch were not significantly changed, fat content was reduced, and protein and ash contents increased. Starch in the rice was degraded, and the particle structure was destroyed, while the crystal structure changed from type A to type V. Thermodynamic properties and solubility both changed. Rice syrup has a high transparency, good rheology, and a more delicate and soft taste.

Cu/Au nanoclusters with peroxidase-like activity for chemiluminescence detection of α-amylase.

Herein, a novel chemiluminescence method was developed for efficient and sensitive detection of α-amylase activity. α-Amylase is closely related to our life, and α-amylase concentration is a marker for the diagnosis of acute pancreatitis. In this paper, Cu/Au nanoclusters with peroxidase-like activity were prepared using starch as a stabilizer. Cu/Au nanoclusters can catalyze H2O2 to generate reactive oxygen species and increase the CL signal. The addition of α-amylase makes the starch decompose and causes the nanoclusters to aggregate. The aggregation of the nanoclusters caused them to increase in size and decrease in the peroxidase-like activity, resulting in a decrease in the CL signal. α-Amylase was detected by the CL method of signal changes caused by dispersion-aggregation in the range of 0.05-8 U mL-1 with a low detection limit of 0.006 U mL-1. The chemiluminescence scheme based on the luminol-H2O2-Cu/Au NC system is of great significance for the sensitive and selective determination of α-amylase in real samples, and the detection time is short. This work provides new ideas for the detection of α-amylase based on the chemiluminescence method and the signal lasts for a long time, which can realize timely detection.

The effects of various enzymatic saccharifications and microwave pretreatment durations on sugar yield and its property alterations of Chinese spirits distillers residues

This study evaluated the effect of different enzymatic hydrolysis and different microwave pretreatment durations on the sugar yield of Chinese spirits distillers residues (CSDR). Addition of both α-amylase and cellulase in the enzymatic hydrolysis of distillers grains resulted in a higher yield of reducing sugar (145.74 ± 4.20 mg·g–1). Fourier transform infrared spectroscopy (FTIR) revealed that different enzyme treatments degraded different functional groups of the cellulose structure. Subsequently, the highest reducing sugar yield (181.33 ± 6.42 mg·g–1) was achieved at microwave pretreatment time of 6 min and was 1.29-fold higher than that of the untreated sample. The differences in the structural features of CSDRs under various microwave pretreatment durations were characterized by scanning electron microscopy, FTIR spectroscopy, and X-ray diffraction. The data revealed that the optimal microwave pretreatment time at 6 min could obviously remove lignin, and then obtain the highest CrI value, achieving the highest reducing sugar yield.

Microbial Community, Fermentation Quality, and in vitro Degradability of Ensiling Caragana With Lactic Acid Bacteria and Rice Bran.

This study aimed to assess the effects of microbial inoculants and growth stage on fermentation quality, microbial community, and in vitro degradability of Caragana silage from different varieties. Caragana intermedia (CI) and Caragana korshinskii (CK) harvested at the budding (BU) and blooming (BL) stages were used as raw materials to prepare silage, respectively. The silages at each growth stage were treated for ensiling alone (control), with 5% rice bran (RB), a combination of RB with commercial Lactobacillus plantarum (RB + LP), and a combination of RB with a selected strain Lactobacillus plantarum L694 (RB + L694). The results showed that the crude protein (CP) content of CI was higher than that of CK, and delay in harvest resulted in greater CP content in Caragana at BL stage. After 60 days of fermentation, the concentrations of lactic acid (LA) in the RB + L694 treatments were higher than those in control treatments (p < 0.05), while the pH, concentrations of NH3-N, neutral detergent fiber with the addition of α-amylase (aNDF) were lower than those in control treatments (p < 0.05). RB + L694 treatments could decrease acid detergent fiber (ADF) content except in CIBL. In CK silages, adding RB + L694 could reduce bacterial diversity and richness (p < 0.05). Compared with the control, RB + L694 treatment contained higher Lactobacillus and Enterobacter (p < 0.05). In vitro NDF and DM degradability (IVNDFD and IVDMD) was mostly affected by growth period, and additive RB + l694 treatment had higher IVDMD and lower IVNDFD than other treatments (p < 0.05). Consequently, the varieties, growth stages, and additives could influence the fermentation process, while the blooming stage should be selected in both Caragana. Furthermore, the results showed that RB and L. plantarum could exert a positive effect on fermentation quality of Caragana silage by shifting bacterial community composition, and RB + L694 treatments outperformed other additives.

An Organoplatinum(II) Metallacycle-Based Supramolecular Amphiphile and Its Application in Enzyme-Responsive Controlled Release.

Enzyme-responsive nanomaterials are emerging as important candidates for bioanalytical and biomedical applications due to their good biocompatibilities and sensitivities. However, the lack of promising operation platforms compatible with enzyme responsiveness greatly limits the scope and functionality of smart materials. Herein, we report the design and synthesis of a naphthalene-functionalized organoplatinum(II) metallacycle 1 by means of coordination-driven self-assembly, which is subsequently exploited as the organometallic platform to enable enzyme-responsive supramolecular materials. Specifically, a [2 + 2] self-assembled metallacycle 1 first self-assembles into nanosheets in aqueous solution, which can further transform into vesicles with the introduction of β-cyclodextrin (β-CD) because of the formation of a bola-type supramolecular amphiphile β-CD-1. Interestingly, these vesicles show rare α-amylase responsiveness, as demonstrated by structurally transforming back into nanosheets after the addition of α-amylase to their solutions due to the enzyme-induced degradation of cyclodextrins. We also demonstrate the potential application of the self-assembled vesicles in amylase-responsive controlled release.

Impact of alpha-amylase enzyme on the Rheological and Microstructural properties of the different types of rice flour doughs and bread

The purpose of this study is to discuss the significant role of the α-amylase enzyme in the production and rheological characteristics of gluten-free rice dough and baked bread. Small deformation and large deformation methods were used to evaluate the effect of the α-amylase enzyme addition on the dough and bread rheological characteristics. The baking properties of bread were evaluated by specific volume, baking loss, and Texture profile analysis parameters. The effect of the added enzyme on the dough microstructure was also evaluated. Small deformation study of doughs showed the highest significant changes after enzyme addition in 0.5S and extra-fine flour doughs. The dynamic rheological study of the flours doughs during the heating period showed significant changes in doughs properties as a function of α-amylase. After enzyme addition, a significant difference in crumb hardness was observed in the fine, semi-coarse, and extra-fine bread. After α-amylase addition in black rice, 0.5S and extra-fine doughs G’, G” and values were decreased. The research explains how the alpha-amylase enzyme effect the rheological characteristics of gluten-free dough and bread. Rheological analysis of doughs made from flour during the heating period indicated that the properties of the doughs were significantly affected by the presence of α-amylase.

Effects of the addition of thermostable α-amylase on the physicochemical and antioxidant properties of extrusion-pretreated Apios fortunei used for yellow wine fermentation

Extrusion-pretreated Apios fortunei was used for yellow wine fermentation. To investigate the effect of thermostable α-amylase on the physicochemical and antioxidant properties of extruded A. fortunei, we used different enzyme concentrations (0–5‰). Enzymatic extrusion increased the degree of gelatinization (84.23–99.99%), water solubility index (28.09–62.75%), reducing sugar content (74.82–263.39 mg/g) and decreased water absorption index (3.25–2.09 g/g) and viscosity (<20 cP) of A. fortunei, these may be beneficial for fermentation. X-ray diffraction and Fourier transform infrared spectroscopy detected that the ordered degree of starch structure decreased with increased enzyme concentration. Molecular-weight analysis indicated that enzyme concentrations of more than 0.5‰ had limited promotion on starch degradation. Scanning electron microscopy observed the eroded surface and holes caused by enzymolysis in enzymatically extruded samples. Enzymatic extrusion increased the phenolic content and antioxidant properties of the samples. Relatively high fermentation efficiency (74.23%) and antioxidant properties (75.87, 76.21 and 203.32 mg of Trolox equivalents/L for DPPH, ABTS and FRAP values, respectively) were observed in wines fermented by extruded samples with 5‰ enzyme. The results indicated that the advantages of enzymatic extrusion in starch degradation and improving the antioxidant properties of A. fortunei could be extended to yellow wine fermentation.

Evaluation of texture, retrogradation enthalpy, water mobility, and anti-staling effects of enzymes and hydrocolloids in potato steamed bread

The functionalities of hydrocolloids and enzymes in texture, retrogradation enthalpy, water mobility and distribution, and anti-staling effects of potato steamed bread stored for 0, 24, and 48 h at 25 °C were investigated. Four kinds of hydrocolloids, including carrageenan, xanthan gum, arabic gum, sodium alginate, and one kind of enzyme (xylanase) showed little effects on the hardness reduction and springiness retention of potato steamed bread during storage, while the presence of α-amylase and lipase could slow down its staling rate. Potato steamed bread with combination of α-amylase (20 mg/kg) and lipase (40 mg/kg) exhibited the lowest hardness, with a significant reduction of 44.20%, besides improving the specific volume, L*, and overall acceptability in sensory evaluation. The addition of α-amylase and lipase could decrease the retrogradation enthalpy and bound water, and increase the mobility of mobile water. These findings shed efficient methods to retard staling of potato steamed bread.

Measuring enzymatic degradation of degradable starch microspheres using confocal laser scanning microscopy

Degradable starch microspheres (DSM) have long been used for topical haemostasis, temporary vascular occlusion and as drug delivery systems. When used for the latter, exact degradation rates of DSM have high importance, as this ensures a controlled and timed drug delivery. Current methods of analysing degradation rates are based on whole batch measurements, which does not yield information regarding individual times of degradation nor does it provide direct correlation measurements between sphere diameter and specific degradation time.In this paper we present an alternative method for measuring degradation rates of biodegradable starch microspheres using confocal laser scanning microscopy (CLSM). We succeeded in visualizing the degradation by staining the DSM and then following the spheres over time in a confocal microscope, after the addition of α-amylase.Individual degradation rates of single spheres could be followed, allowing a precise correlation measure between sphere size and degradation time. Furthermore, physical abnormalities such as internal cavities were detected within some spheres. These physical differences also had a measurable effect on the rate of degradation. Finally, complete degradation rates could be determined very accurately.To our knowledge, this is the first paper in which DSM degradation is visualized and measured using CLSM. Statement of significanceUsing degradable starch microspheres as a drug delivery system, is a continuously evolving field which shows promise in several different areas of illnesses. This paper presents a new method which visualizes enzymatic degradation of starch microspheres in real-time using confocal microscopy. The method is simple, yet the versatility of it suggests that it could be broadly applied within the field of biodegradation. Here, it illuminates a previously uninvestigated parameter: the effect of physical sphere deformities on the rate of degradation. It also provides precise correlation measures between initial sphere size and time of complete degradation.

Microparticle prepared by chitosan coating on the extruded mixture of corn starch, resveratrol, and α-amylase controlled the resveratrol release

Microcapsule was developed by chitosan coating on the microparticle which was prepared by smashing the extruded mixture of corn starch, resveratrol, and α-amylase. In the preparation process, the low-temperature extrusion and α-amylase were employed to overcome the disadvantages of low gelatinization, dissolution, and poor hydration of extruded starch. Chitosan-coating retarded starch aging, improved the stability of microcapsules, delayed the release of resveratrol. Considering the bioactive functions of chitosan, microcapsules also obtained the functions of chitosan by chitosan coating. The chitosan coating and α-amylase addition improved the release ratio of resveratrol. CESRA (chitosan solution (2%) coating on the extruded mixture of corn starch, resveratrol, and α-amylase) released 86.8% resveratrol at 25 °C in six days chasing, and 85.3% resveratrol at 37 °C in 48 h chasing. Chitosan coating slightly improved the free radical scavenging activity of ABTS+. The particle size variation, SEM, XRD, and FT-IR were also employed to investigate the variation of morphology, crystal structure, and chemical composition.

The Physical Adsorption of Gelatinized Starch with Tannic Acid Decreases the Inhibitory Activity of the Polyphenol against α-Amylase.

The effects of mixing orders of tannic acid (TA), starch, and α-amylase on the enzyme inhibition of TA were studied, including mixing TA with α-amylase before starch addition (order 1), mixing TA with pre-gelatinized starch before α-amylase addition (order 2) and co-gelatinizing TA with starch before α-amylase addition (order 3). It was found that the enzyme inhibition was always highest for order 1 because TA could bind with the enzyme active site thoroughly before digestion occurred. Both order 2 and 3 reduced α-amylase inhibition through decreasing binding of TA with the enzyme, which resulted from the non-covalent physical adsorption of TA with gelatinized starch. Interestingly, at low TA concentration, α-amylase inhibition for order 2 was higher than order 3, while at high TA concentration, the inhibition was shown with the opposite trend, which arose from the difference in the adsorption property between the pre-gelatinized and co-gelatinized starch at the corresponding TA concentrations. Moreover, both the crystalline structures and apparent morphology of starch were not significantly altered by TA addition for order 2 and 3. Conclusively, although a polyphenol has an acceptable inhibitory activity in vitro, the actual effect may not reach the expected one when taking processing procedures into account.

Formation and thermal and colloidal stability of oil-in-water emulsions stabilized using quinoa and lentil protein blends.

The amino acid composition, and rheological, thermal and colloidal stability of plant protein-based oil-in-water emulsion systems containing 1.90, 3.50 and 7.70 g 100 mL-1 protein, fat and carbohydrate, respectively, using quinoa and lentil protein ratios of 100:0 and 60:40 were investigated. The emulsion containing lentil protein showed lower initial, peak and final viscosity values (22.7, 61.7 and 61.6 mPa s, respectively) than the emulsion formulated with quinoa protein alone (34.3, 102 and 80.0 mPa s, respectively) on heat treatment. Particle size analysis showed that both samples had small particle sizes (~1.36 μm) after homogenization; however, the sample with 60:40 quinoa:lentil protein ratio showed greater physical stability, likely related to the superior emulsifying properties of lentil protein. However, upon heat treatment, large aggregates (~100 μm) were formed in both samples, reducing the physical stability of the samples. This physical stability was increased with the addition of 0.20% sodium dodecyl sulfate (SDS), whereas it was negatively affected by the addition of α-amylase. Addition of α-amylase led to lower viscosity for both emulsion samples, with measured values of 41.8 and 46.0 mPa s for the 100:0 and 60:40 samples, respectively. This suggests that the heat-induced increases in particle size were partially due to hydrophobic interactions between the proteins as SDS disrupts hydrophobic bonds between proteins. These results demonstrated that using a mixture of lentil and quinoa proteins positively affected the physical stability of plant protein-based emulsions, in addition to contributing to a more nutritionally complete amino acid profile - both important considerations in the development of plant-based beverages. © 2021 The Authors. Journal of The Science of Food and Agriculture published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry.

Effects of α-amylase and wheatgrass supplement on fermentation process, textural, antioxidant and sensory properties of steamed white honeycomb cakes

In this study, the usage of α-amylase and wheatgrass powder supplement was investigated to reduce the fermentation duration and fortify the nutritional values of banh bo (white honeycomb cake), an indigenous cake made from rice flour and tapioca starch in Vietnam. The results indicate that the addition of 0.05 wt% and 0.07 wt% α-amylase could significantly reduce total fermentation duration from 11 to 6 h while the fortification with 0.5–2 wt% wheat grass did not significantly influence the process. All the batters exhibited strong non-Newtonian behavior, but higher consistency of batters was obtained with the addition of α-amylase. All the resultant cakes did not display a significant difference in porosity, except the cake of 0.2 wt% wheat grass. The hardness and chewiness values decreased gradually with the increase in added enzyme content, but their increasing trends were observed with the addition of wheatgrass. The supplement of wheatgrass powder significantly increased the contents of chlorophyll and phenolic compounds, which both were responsible for the increments in antioxidant capacity. Hedonic tests indicate that the sensory attributes of the final products were successfully maintained. The study may provide insights in cereal-based fermented foods.

Novel porous starch/alginate hydrogels for controlled insulin release with dual response to pH and amylase.

An important principle in the development of oral insulin is to protect insulin from the harsh conditions of the stomach and release it in a controlled manner in the intestine. In the present study, novel insulin-loaded porous starch-alginate hydrogel systems (In-S-Alg) including In-MS-Alg (prepared with porous maize starch), In-WS-Alg (porous waxy maize starch), and In-RS-Alg (porous rice starch) were successfully developed. As a representative, In-MS-Alg was further coated with gelatinized-retrograded high amylose maize starch (HA) films with different thicknesses to prepare In-MS-HA/Alg hydrogel beads for improving the functionality of controlled release of insulin under the action of α-amylase. The In-S-Alg and In-MS-HA/Alg hydrogel beads were evaluated in terms of structural and morphological properties, encapsulation effect on insulin as well as its release behavior. The results show that insulin was distributed in the pores and cavities of porous starch granules. In In-MS-HA/Alg hydrogel beads, insulin was increasingly blocked inside porous starch with the increased thickness of the HA film. Encapsulation efficiency of insulin in all In-S-Alg and In-MS-HA/Alg hydrogel beads was >80%. Amazingly, both the hydrogel beads successfully achieved the goal of triggered release upon pH changes and α-amylase addition. Most of the insulin (about 90%) was retained in the simulated gastric fluid; while the release rate of insulin in the simulated intestinal fluid increased gradually, and was further accelerated in the presence of α-amylase. Furthermore, for the In-MS-HA/Alg hydrogel beads, the insulin release rate can be gradually reduced by increasing the thickness of the HA film, which provided the possibility to match the rate of increase of the blood glucose level after the intake of food with different glycemic indices. Therefore, the novel hydrogel prepared in this study may be a promising and safe delivery carrier for oral insulin.

Exogenous α-amylase supplementation reduces the variability of ileal digestible energy in broiler chickens fed complete diets with maize batches of variable protein solubility

This study evaluated the relationship between salt-soluble protein (SSP) of maize and the apparent ileal digestibility (AID) of complete diets in response to exogenous α-amylase supplementation in broiler chickens. Samples of 12 maize batches originating from the mid-north and northeast of China were analyzed for SSP. Six of the 12 sources of maize with a wide variation of SSP (from 21.1 % to >50 %) were selected. Six maize-soybean meal basal diets were formulated, including each source of maize with or without the addition of α-amylase (Ronozyme® HiStarch; DSM Nutritional Products). A total of 960 day-old male Arbor Acres Plus broiler chickens were randomly allocated to 12 treatments with 8 replicates per treatment in wired cages and fed experimental diets in 2 phases (d 1−14; d 15−28). At d 28, 4 birds selected from each cage were euthanized for evaluation of apparent ileal digestibility (AID) of starch and energy. The addition of α-amylase reduced the feed conversion ratio (FCR) of chickens from 1 to 28 d (1.407 vs. 1.426) compared to the basal diets across maize batches, particularly from 1 to 7 d (1.049 vs. 1.078). An interaction between maize batch and α-amylase supplementation on FCR was detected only at 7 d, when the batch with the lowest SSP exhibited the greatest response to α-amylase. Neither a main effect of α-amylase nor an interaction with maize batch on AID of starch were detected (P > 0.05). Nonetheless, α-amylase supplementation increased ileal digestible energy (IDE) from 12.21 to 12.50 MJ/kg dry matter across maize batches. These increments were mainly driven by the maize batch with the lowest SSP. α-amylase supplementation reduced the variability of IDE from a coefficient variance (CV)=5.2 % to a CV=0.7 % across maize batches. Interestingly, there was a strong negative correlation (r<-0.95; P < 0.001) between the initial IDE of maize and the IDE response to α-amylase, and a less strong correlation between SSP and the IDE response to α-amylase (r=-0.78, P = 0.07). SSP was not a predictor of starch digestibility at this age. Dietary α-amylase supplementation has the potential to significantly reduce the variability in the energy value of maize-based diets in commercial poultry production by improving the nutritional value of poorly digestible maize.

CARBOHYDRATE DEGRADATION OF TUBER PASTE FLOUR BY THE ADDITION OF α-AMYLASE FROM TWO Lactobacillus SPECIES

The quality of Indonesia tuber flour can be improved by α-amylases which hydrolyzes the flour amylose to glucose and maltose. These monosaccharides causes the flour to have better homogeniety similar to wheat flour and easier to digest. This research aimed at investigating carbohydrate degradation of tuber paste flour by the addition of α-amylase from two Lactobacillus species. Lactobacillus species used were Lactobacillus bulgaricus and L. plantarum B110, while the flour types were made of local taro ( Colocasia esculenta ), gadung ( Dioscorea hispida ) and sweet potato ( Ipomoea batatas ), as well as wheat ( Triticum ) as a reference. Crude α-amylase activity and reducing sugars were detected by the Dinitrosalycylic acid (DNS) method. Data were statistically analyzed with ANOVA. Research results indicated that α-amylase from L. bulgaricus and L. plantarum B110 have been characterized for their optimum activity and stabilitiy. The reducing sugar content in taro, gadung , sweet potato paste flour and wheat paste flour added with α-amylase of L. bulgaricus increased by 0.008, 0.006, 0.004 and 0.001%, respectively. Meanwhile, the reducing sugars of the above flours added with amylase from L. plantarum B110, increased by 0.008, 0.008, 0.008, and 0.003%, respectively. Increase in reducing sugar contents in carbohydrate degradation of local tuber paste flour added with L. bulgaricus α-amylases was higher than that in wheat paste flour with a 0.001% increase. Similarly, the 0.008% increase of sugar content in tuber paste added with L. plantarum B110 α-amylase was also higher than that in wheat flour with 0.003% increase. Therefore, local tuber paste flour can be used as an alternative to wheat paste flour.