Encapsulation of quercetin fraction from Musa balbisiana banana blossom in chitosan alginate solution, its optimization and characterizations.

This study comprises the isolation of quercetin from the bhimkol banana (Musa balbisiana) blossom, encapsulation, and its characterizations. An isolated quercetin rich fraction was obtained from HPLC followed by column chromatography and subsequently encapsulated with chitosan-alginate polyelectrolyte complex at optimum encapsulation conditions obtained by ant colony optimization. Quercetin fraction and encapsulated quercetin were characterized for their physicochemical properties (by HPLC, FTIR, NMR, XRD, Dynamic Light Scattering, and release study). The yield and purity of isolated quercetin rich fractions were 2.35 ± 0.08 µg/ml and 83.12 ± 0.31 %, respectively. After the optimization of encapsulation, quercetin 0.2 %, sodium alginate 4 %, chitosan 0.5 %, and agitation at 300 rpm were found to be the optimal conditions resulting in higher encapsulation efficiency (EE, 84.54 %). EE was significantly improved by a slight increase in sodium alginate, and agitation. Encapsulated quercetin revealed good pH resistance by releasing 68.27 mg QE/g quercetin in simulated gastric fluid at 60 min. Microbeads of encapsulated quercetin showed the structural bond stretching of encapsulating materials and quercetin in FTIR spectra (stretching at 1511 cm-1, 1380 cm-1, and 1241 cm-1 are attributed to the stretching vibration of CO in aromatic rings, and bending vibration of OH bond in phenols). An average particle size of 2.71 µm exhibited the microgel behavior of microbeads (by XRD). The present study on the underutilized variety of banana blossoms has diverse applications in the food and pharmaceutical industries that will productively exhibit effective drug delivery properties.

Preparation, physicochemical characterization, and in vitro starch digestibility on complex of Euryale ferox kernel starch with ferulic acid and quercetin.

The objective of the current research was to analyze the physicochemical, structural, and in vitro starch digestibility of Euryale ferox kernel starch (EFKS) in complexation with ferulic acid (FA) and quercetin (QR). XRD results have shown that FA and QR were attached to starch resulting crystalline complexes. SEM image showed a smooth, compact structure, indicating FA and QR assist in the reorganization of starch molecules. The 1H NMR spectra of starch-polyphenols complexes showed multiple additional peaks between 6.00 and 9.00 ppm due to the benzene ring and phenolic hydroxyl groups imparted from polyphenols. The shifting and emergence of the characteristic peak observed in the DSC thermogram confirmed that polyphenols were successfully attached to starch. Complexation alters colors, reduced swelling power, and increased the solubility of the complexes. Following the complexation of FA and QR, the content of resistant starch exhibited a significant rise, escalating from 7.69 % (control sample) to 49.39 % (10 % FA) and 54.68 % (10 % QR). This led to a notable reduction in the predicted glycemic index (pGI).The higher resistant starch in the complex is attributed due to the combined effects of the reordered structure of the complexes and the inhibitory activity of polyphenols against starch digestive enzymes. Therefore, EFKS-FA and EFKS-QR complex can be used as a functional ingredient for a low glycemic index food.

Effect of Euryale ferox seed shell extract addition on the in vitro starch digestibility and predicted glycemic index of wheat-based bread.

The inhibitory effects of Euryale ferox seed shell extract (EFSSE) on the activity of α-amylase and α-glucosidase were studied. EFSSE (0.25 % to 2 %) was used to fortify bread and analyzed the in vitro starch digestibility (IVSD) digestion kinetics, and the predicted glycemic index (pGI) was estimated. The swarm intelligence supervised neural network (SISNN) technique was applied for the predictive simulation of digestion kinetics and pGI. Principal component analysis (PCA) with proportional odds modeling (POM) was used to find the most sensitive component based on the sensory attributes of bread. The inhibitory effect of EFSSE on α-amylase and α-glucosidase in terms of IC50 was 62.95 and 52.06 µg/mL, respectively. Fortification of bread with EFSSE could affect loaf volume, hardness, and color. Euryale ferox seed shell extract could decreased the rate of hydrolysis of bread. EFSSE (2 %) had a strong inhibitory impact, as evidenced by the drop in glycemic index from 94.61 to 61.66. SISNN-based kinetics was much better as compared to mathematical modeling-based digestion kinetics. Findings of the present study have shown that EFSSE could be employed as an additive to produce lower glycemic index functional bread.

Sensory evaluation of microwave-ultrasound treated bottle gourd juice using hybrid features of fuzzy logic and proportional odd modelling approach.

In the present investigation, sensory evaluation of bottle gourd juice (BGJ) samples, obtained from microwave-ultrasound based combined treatment was performed. The raw (sample-1) and conventionally treated (sample-2) alongside microwave-ultrasound treated (sample-3) were considered for the assessment of sensory evaluation. An innovative approach of hybrid fuzzy logic and proportional odd modelling (FL-POM) was implemented for the analysis of the sensory scores. The similarity values for the juice samples and their quality attributes were resolved from the results obtained by fuzzy logic. These values were considered as input for hybridization with the POM approach. The assessed coefficients obtained from the results of POM were considered for the ranking of the samples and quality traits. The ranking of the BGJ samples was observed in the order of sample-1 > sample-3 > sample-2, and their related quality attributes ranked in the order color > taste > aroma > mouth feel. The microwave-ultrasound treated BGJ evinced as the best sample in comparison to the raw one.

Synthesis of salicylic acid phenylethyl ester (SAPE) and its implication in immunomodulatory and anticancer roles.

Salicylic acid phenylethyl ester (SAPE) was synthesized by Zn(OTf)2-catalyzed selective esterification of salicylic acid and phenylethyl alcohol and studied for its role as an immunomodulatory and anticancer agent. Low toxicity and favorable physical, Lipinski-type, and solubility properties were elucidated by ADME-tox studies. Molecular docking of SAPE against COX-2 revealed favorable MolDockscore, rerank score, interaction energy, internal pose energy, and hydrogen bonding as compared to ibuprofen and indomethacin. An average RMSD of ~ 0.13 nm for the docked complex with stable dynamic equilibrium condition was noted during the 20 ns MD simulation. A low band gap predicting a strong binding affinity at the enzyme's active site was further predicted by DFT analysis. The ester caused a reduction in the percentage of erythrocyte hemolysis and was shown to be non-cytotoxic against human lymphocytes, CaCo-2, and HepG-2 cells by the MTT assay. Moreover, it's in vitro efficacy in inhibiting COX-2 enzyme under both LPS stimulated intestinal cells and direct sequestration assays was found to be higher than salicylic acid and indomethacin. The anticancer activity of SAPE was tested on the breast cancer cell line MCF-7, and potential efficacy was exhibited in terms of decreased cell viability. Flow cytometry analysis exhibited the arrest of the cell cycle at G1/G0 and S phases, during which induction of autophagic vesicle formation and decrease in mitochondrial membrane potential was observed owing to increased ROS production. Furthermore, at these phases, the onset of apoptosis along with DNA damage was also observed. Pre-treatment with SAPE in colitis-induced Wistar rats displayed low disease activity index and reduction in the extent of intestinal tissue disruption and lipid peroxidation. A marked increase of anti-oxidative enzymes viz., catalase, GGT, and GST, and a decrease of pro-inflammatory cytokines IL-6 and TNF-α in the intestinal tissue extracts of the treated groups was noted. The results of this study have sufficient credence to support that the synthesised ester (SAPE) be considered as an anti-oxidative and anti-inflammatory compound with therapeutic potential for the effective management of cancer.

Application of microwave and hydrothermal treatments for modification of cassava starch of Manipur region, India and development of cookies.

The cassava (Manihot esculenta) root provides sustainable cheap source of starch that can be modified using microwave and hydrothermal treatments. The modified starch is of great demand in the market for its varied food applications. The microwave modified wet milling dry chips starch, microwave modified pulp starch (MD-PS), microwave modified dry chips starch were the microwave treated starch obtained from starches of pulp starch (PS), wet milling dry chips starch and dry milling dry chips starch, respectively. On the other hand, by using hydrothermal treatment followed by freeze-drying in PS gave autoclave freeze-dried 10% PS (AF-10PS), autoclave freeze-dried 20% PS (AF-20PS). The physicochemical and functional properties of the samples were investigated. The calorific value of modified starch was found to be 341-358 kcal/100 g. The microwave-modified starch lowered true densities as compared to hydrothermal treated starch. FT-IR spectra of microwave-modified starch confirmed six prominent peaks between 4500-500 cm-1. Thermal treatment affected the digestibility and found lower digestion resistibility in modified starch compared to native starch. The structures of the starch granules were more enzymatically susceptible in hydrothermally modified starch. The microwave-modified starch resulted higher resistant starch as compared to hydrothermally modified starch. The cookies quality using MD-PS was checked by developing with 10-40% level of substitution of wheat flour. Overall cookies acceptability was found above sensory score 5. This study will help to provide functional ingredients that serve health benefit beyond nutrition.

Physicochemical and phytochemical properties of foam mat dried passion fruit (Passiflora edulis Sims) powder and comparison with fruit pulp.

The aim of the present study was to develop purple passion fruit powder using the foam mat dried process. The possible effect of whipping time, methylcellulose concentration, and drying temperature on physicochemical and phytochemical properties of foam mat dried passion fruit was evaluated and compared with fruit pulp. The drying process was optimized using central composite design and optimum conditions were whipping time 2.78 min, methylcellulose 2.58%, temperature 44.05 °C. At the optimum condition vitamin C, total phenolic compound and hygroscopicity were 34.67 mg/100 g, 258.12 mg GAE/100 g, and 21.12%, respectively. The artificial neural network was applied to predict experimental outcomes. The phytochemical properties in terms of (±)-α tocopherol, D-α-tocotrienol, ß-carotene, and phenolic acid were determined using RP-HPLC. The foam mate dried powder contained a higher amount of ß-carotene (13.26 mg/100 g), total phenolic compound (258.12 mg/100 g) and phenolic acids than fruit pulp whereas fruit pulp was contented higher amount of (±)-α tocopherol (171.1 mg/100 g) and D-α-tocotrienol (27.19 mg/100 g). The study manifested foam mate drying as an effective way to develop passion fruit powder.

GC-HRMS screening of bioactive compounds responsible for antimicrobial and antioxidant activities of blood fruit (Haematocarpus validus Bakh. F. Ex Forman) of North-East India.

The aims of this study are to evaluate phytochemical composition, antimicrobial and antioxidant activities of different solvent-assisted blood fruit pulp extracts. The extracts of blood fruit were prepared with various solvents namely, water, ethyl acetate, methanol and acetone. These extracts were divided into two groups, first group of extract were thermosonicated (treated) and the second group were not exposed to thermosonication (untreated). The sample extracts were then evaluated for their antimicrobial properties against various microorganisms. The results revealed that the antimicrobial activity of thermosonicated ethyl acetate extracts at 12 mg/mL concentration exhibited the highest inhibition zone of 19.4 mm against Staphylococcus aureus. The phenolic content of ethyl acetate extract was found to be the highest as compared to that of other solvent extracts and the values were 1508.08 and 1478.34 mg GAE/100 g for treated and untreated samples, respectively. The treated ethyl acetate extract antioxidative activity by DPPH, ORAC, ABTS, and FRAP assay were 1627.68, 2119.82, 938.11, and 2360.18 µmol TE/g, respectively. The minimum bactericidal concentration (MBC - 1.5 mg/mL) against the selected foodborne pathogens was obtained with thermosonicated ethyl acetate blood fruit extract. In the present study, it was observed that the thermosonicated ethyl acetate extract exhibits maximum antioxidant and antimicrobial activities than any other examined solvent extracts. The major bioactive volatile compounds found in treated ethyl acetate extracts were 2-bromotetradecane, tetracosane, heptadecane, eicosane and palmitic acid. These bioactive compounds can be utilizable for the development of functional, nutraceutical and pharmacological products.

Optimized microwave-assisted extraction of bioflavonoids from Albizia myriophylla bark using response surface methodology.

Bioflavonoids are of great interest due to their health-benefitting properties and possible protection against certain types of diseases. A microwave-assisted extraction (MAE) method was investigated for maximum retention of total bioflavonoids from Albizia myriophylla bark (AMB). Response surface methodology (RSM) using central composite design were employed for obtaining the best possible combination of MAE process parameters including microwave power (400-900 W), liquid/solid ratio (20-40 ml/g), extraction time (20-40 min) and ethanol concentration (60-100%). Optimum conditions of extraction under which predicted maximum bioflavonoids yield of 152.74 mg QE/g DW and antioxidant activity of 75.33% in close proximity with the experimental values were: microwave power 728 W, liquid/solid ratio 24.70 ml/g, extraction time 39.86 min and ethanol concentration 70.36%. Satisfactory statistical parameters (R2), ANOVA for the model and lack-of-fit testing provided an adequate mathematical description of the MAE of bioflavonoids with high antioxidant activity. Therefore, MAE of AMB using RSM could be termed as a time-saving and an efficient method resulting to high yield with increased antioxidant activity. Also, HPLC analysis of AMB revealed the presence of bioflavonoids viz., naringin, quercetin and apigenin; which may be further extensively studied for use as therapeutics against various health issues.

Process optimization for the production of blood fruit powder by spray drying technique and its quality evaluation.

Blood fruit (Haematocarpus validus) has important bioactive compounds, antioxidant properties and some essential minerals, which plays an essential part in human nutrition and traditional medicine for treating arthritis, jaundice, hypertension, cancer, etc. This work was conducted to optimize the parameters of spray drying process for production of blood fruit juice powder and its quality was compared with freeze dried and tray dried powder. It was observed that powder produced by spray drying techniques resulted in higher yield, solubility and better retention of resveratrol content and was considered to be of superior quality, having a higher degree of reconstitution ratio as compared to powders produced by freeze and tray drying techniques. High performance liquid chromatography study of blood fruit powder showed the presence of resveratrol and other phenolic compounds. Scanning electron microscope was used to study the surface morphology and it revealed that spray-dried powder has uniformity in shape and size as compared to freeze dried and tray dried powder. The present investigation indicated that spray drying results in better, superior quality powders that are easier for packaging, transportation, having better shelf life.

Ultrasound-assisted extracted dietary fibre from culinary banana bract as matrices for anthocyanin: its preparation, characterization and storage stability.

Dietary fibre (DF) functionalized with polyphenols is a functional ingredients as it provides the health benefits associated with consumption of both DF and polyphenols. The present study endeavoured to prepare DF-anthocyanin formulation with different ratio of pigment-matrix where DF and anthocyanin were extracted from culinary banana bracts. The formulated powders were studied for its antioxidant, structural properties and fluorescent properties. DF-anthocyanin formulation exhibited enhancement in anthocyanin content with increase in antioxidant content and it was highest for DF-A3 with better color values (L*, a*, C*) compared to other formulations. The structure of the formulation was mainly attributed to the structure of DF and anthocyanin as evidenced by FT-IR. Moreover, changes in the degree of crystallinity were found after addition of anthocyanin in fibre matrix. The morphology study by SEM confirmed the entrapment of particles (1.97-3.88 µm) on the network structure and surface of DF. Additionally, Akin fluorescence emission spectra of DF-A3 with anthocyanin extract further confirmed the formation of DF-anthocyanin complex. Storage stability study showed DF-A3 with lowest degradation rate (k = 0.0002 day-1) and half-life period of 87 days.

Chemical profiling and functional properties of dietary fibre rich inner and outer bracts of culinary banana flower.

The present study endeavoured to evaluate the nutritional, phytochemical and functional properties of outer and inner bracts of culinary banana flower which is a by-product of banana production. Both outer and inner bracts were found to be rich in dietary fibre (61.13 and 66.22%, respectively) along with other chemical compositions including proximate, minerals, and antioxidant-rich phenolics both free and bound. In addition, the functional properties including glucose dialysis retardation index (GDRI) of outer and inner bracts were also studied. The outer and inner bracts exhibited total polyphenols 7.56 and 9.44 mg phenols/g dry sample, respectively. The polyphenol profile by HPLC, revealed the presence of significant amount of free and bound phenolics in both outer and inner bracts. Functional properties of these dietary fibres-rich fractions of culinary banana flower exhibited lower bulk density, higher water-holding capacity, oil-holding capacity, and water-swelling capacity in outer and inner bracts than cellulose. The outer and inner bracts showed relatively higher GDRI compared to control and cellulose. The results revealed that both the outer and inner bracts of culinary banana flower are rich source of dietary fibre along with high antioxidant activity and could be one of the promising functional ingredients for low-calorie and high-fibre food product.

Growth and metabolic characterization of four lactic acid bacteria species isolated from rice beer prepared in Assam, India.

Isolation and identification of lactic acid bacteria (LAB) from rice beer prepared in Assam, India was performed and their growth associated and functional properties were studied. LAB strains were identified as Lactobacillus casei , Pediococcus pentosaceus , Lactobacillus pentosus and Lactobacillus plantarum based on 16 s rRNA sequencing. Their growth characteristics at different pH, NaCl concentration, temperature and presence of carbohydrates were profiled. High tolerance against acid and bile salts was shown by all the strains, particularly L. pentosus TEZU174 and P. pentosaceus TEZU199 up to a pH of 1.5, and L. pentosus TEZU174 up to 14  % bile concentration. They were susceptible towards the common antibiotics, wherein erythromycin, chloramphenicol and linezolid were the most effective. The strains displayed antibiosis activity against Escherichia coli and Staphylococcus aureus and antioxidant activity in terms of resistance to H2O2, scavenging of ·OH and DPPH free radicals was also displayed, wherein L. casei TEZU374 and P. pentosaceus TEZU482 were the most effective with above 70  % scavenging activity. The strains displayed cellular aggregation and L. casei TEZU262 and L. casei TEZU309 were highly aggregated, which attained 100  % autoaggregation within a period of 5 h. High cell surface hydrophobicity was shown by L. casei TEZU309 towards xylene and chloroform, and P. pentosaceus TEZU427 towards ethyl acetate. The strains evinced good gut tolerance capacity, antioxidant activity and adherence properties, which are characteristics of probiotic bacteria and thus are candidates for therapeutic uses and also to be used as starter cultures.

Bioflavonoids from Artocarpus heterophyllus lam. and Cyclosorus extensus (blume) H. Itô as preservatives for increased storage stability of rice beer.

The purified ethanolic extracts of Artocarpus heterophyllus Lam. contained myricetin and epigallocatechin gallate and that of Cyclosorus extensus (Blume) H. Itô contained kaempferol, luteoline and quercetin, in high amount, along with some other flavonoids. Rice beers were fortified with these extracts and kept at 32 °C for 8 weeks, and storage parameters were compared with synthetic antioxidant added and filtered rice beers. It was observed that the aerobic plate counts were significantly less (p ≤ 0.01) in the fortified beers, along with a reduction in the rate of pH fall and change of colour (ΔE). The antioxidant activity (DPPH scavenging) was highest in the fortified beers, along with a delay in lipid peroxidation (POV and TBARS values). The overall study indicated effectiveness of the flavonoid rich extracts in improving the shelf-life stability of rice beer under accelerated conditions.

Effect of extrusion conditions on the physicochemical and phytochemical properties of red rice and passion fruit powder based extrudates.

The passion fruit powder blended rice flour based extrudate was developed and investigated in terms of physicochemical and phytochemical properties. The extrusion process was performed using a twin screw extruder and optimized using rotatable central composite design followed by response surface methodology. The effect of process parameters such as temperature (80-150 °C), screw speed (200-400 rpm), moisture content (20-30%) and passion fruit powder (0-15%) on product quality was investigated. The optimum extrusion conditions of temperature, screw speed, feed moisture content, and passion fruit powder were 97.50 °C, 250 rpm, 25.20% and 11.25%, respectively. At optimum condition, the predicted values of responses were expansion ratio 8.05, water absorption index 2.77, total phenolic content 129.492 mg GAE/100 g and DPPH scavenging activity 65.79%. A comparison between optimized and control extrudates revealed that thermal, crystallinity and morphological properties of extrudates differed significantly. The comparison was also conducted in terms of FT-IR, SEM-EDS and HPLC analysis. The phytochemical properties showed that ß-carotene, cyanidin-3-glucoside, peonidin-3-D-glucoside chloride were higher in control whereas the optimized sample evinced more (±)-α-tocopherol and D-α-tocopherol.

Thermodynamics of sorption isotherms and storage stability of spray dried sweetened yoghurt powder.

Sorption isotherm is a quantitative approach to predict the shelf life of dried foods. Adsorption isotherms of spray dried sweetened yoghurt powder (SYP) were determined by static gravimetric technique at 20, 30, 40 and 50 °C. The data obtained were fitted to eight different sorption models. A non-linear least square regression analysis was adopted to evaluate the model constants. The experimental sorption data were best fitted to four parameter Peleg model. The monolayer moisture contents found from GAB model were 4.88, 4.54, 3.86 and 3.52% at 20, 30, 40 and 50 °C, respectively. The maximum net isosteric heat of sorption and sorption entropy of SYP were 9.399 kJ/mol and 20.28 J/mol K, respectively. The Gibb's free energy change for sorption was in the range 3436.19-303.91 J/mol. The storage stability in terms of moisture content, thiobarbituric acid, free fatty acid, hydroxymethyl furfural values and starter counts of SYP packed in aluminium laminated polyethylene (ALPE) and low density polyethylene (LDPE) were studied along with their change kinetics. The relationship between the water vapour permeability of packaging materials and adsorbed moisture (determined from GAB equation) in powder was used to predict the shelf life and was predicted as 28 and 44.44 days in LDPE and ALPE pouches, respectively.

Effect of hydrocolloids on the physico-chemical and rheological properties of reconstituted sweetened yoghurt powder.

BACKGROUND: The consistency of sweetened yoghurt (misti dahi) is a desired characteristic which is attributed to the casein protein network formation during fermentation. Unfortunately, this property is lost in reconstituted sweetened yoghurt (RSY) due to the irreversible nature of protein denaturation during spray drying. Therefore, this study aimed to increase the consistency of RSY using different hydrocolloids. RESULTS: The effects addition of guar gum, pectin, κ-carrageenan and gelatin (0.1%w/v each) on the physico-chemical, microbial, rheological and sensory properties of RSY were investigated. RSY with 40% total solids demonstrated the rheological properties which are very similar to those of fresh sweetened yoghurt. RSY containing different hydrocolloids further increased the rheological properties. The dynamic rheological study revealed that the magnitude of storage modulus (G'), loss modulus (G″), and loss tangent (tan δ) were significantly influenced by the addition of hydrocolloids and gelatin exhibited highest dynamic moduli in RSY. However, κ-carrageenan added RSY was preferred sensorially as the rheological properties were very close to gelatin added RSY. Addition of hydrocolloids significantly increased the starter bacteria count and pH and reduced water expulsion rate (P < 0.05). CONCLUSION: Addition of hydrocolloids can improve the rheological properties of reconstituted yoghurt. The study concluded that the addition of κ-carrageenan showed better results in terms of rheological and sensory properties of RSY. © 2017 Society of Chemical Industry.

Optimization of ultrasound and microwave assisted extractions of polyphenols from black rice (Oryza sativa cv. Poireton) husk.

Phenolic compounds were extracted from the husk of milled black rice (cv. Poireton) by using a combination of ultrasound assisted extraction and microwave assisted extraction. Extraction parameters were optimized by response surface methodology according to a three levels, five variables Box-Behnken design. The appropriate process variables (extraction temperature and extraction time) to maximize the ethanolic extraction of total phenolic compounds, flavonoids, anthocyanins and antioxidant activity of the extracts were obtained. Extraction of functional components with varying ethanol concentration and microwave time were significantly affected by the process variables. The best possible conditions obtained by RSM for all the factors included 10.02 min sonication time, 49.46 °C sonication temperature, 1:40.79 (w/v) solute solvent ratio, 67.34% ethanol concentration, and 31.11 s microwave time. Under the given solutions, the maximum extraction of phenolics (1.65 mg/g GAE), flavonoids (3.04 mg/100 g), anthocyanins (3.39 mg/100 g) and antioxidants (100%) were predicted, while the experimental values included 1.72 mg/g GAE of total phenolics, 3.01 mg/100 g of flavonoids, 3.36 mg/100 g of anthocyanins and 100% antioxidant activity. The overall results indicated positive impact of co-application of microwave and ultrasound assisted extractions of phenolic compounds from black rice husk.

Amylolytic fungi in starter cakes for rice beer production.

Two types of starter cakes, viz. amou and perok-kushi, used in the production of rice beer in Assam, India, by the Bodo and Deori communities, respectively, were used for the isolation of amylolytic fungi. Based on the sequencing of their internal transcribed spacer (ITS) regions the fungi were identified as Amylomyces rouxii and Rhizopus oryzae, and given the strain names TU460 and TU465, respectively. Both the strains showed the ability to degrade and saccharify starch. The glucoamylase activity was considerably high in A. rouxii TU460 (14.92 µmol/min) as compared to R. oryzae TU465 (1.41 µmol/min), whereas α-amylase activity was found to be closely related, i.e. 7.02 and 6.09 unit mL-1, respectively. SDS PAGE for the determination of the molecular size of the glucoamylase enzymes revealed the production of two distinct units of 59 kDa and 31 kDa by A. rouxii TU460, and one unit of 72 kDa by R. oryzae TU465. LC MS/MS analysis revealed that no mycotoxins were produced by either of the strains. The overall study indicated a good amylolytic property of both strains and a potential for application in the starch processing industries.

Effect of microencapsulation using extrusion technique on viability of bacterial cells during spray drying of sweetened yoghurt.

An improved extrusion spraying technique was employed for encapsulation of mixed bacteria culture of Streptococcus thermophilus and Lactobacillus bulgaricus using sodium alginate as the coating material for the purpose of better survival during spray drying of sweetened yoghurt. The effects of nozzle air pressure (200, 300, 400 and 500kPa), sodium alginate concentration (1%, 1.5%, 2%, 2.5% and 3% w/v), calcium chloride concentration (0.1, 0.2, 1M) and hardening time (15, 30, 45 and 60min) on the viability of encapsulated bacteria were investigated. Alginate concentration increased the microcapsule size whereas, nozzle air pressure decreased the size. The encapsulation efficiency increased with the size of microcapsules. Hardening time exhibited a positive effect up to 30min then the effect was non-significant. Increased level of sodium alginate significantly increased the survival ratio of encapsulated bacteria cells. The survival ratio of bacteria cells during spray drying of sweetened yoghurt were 2.48×10-1 and 2.36×10-3 for encapsulated and free cells of S. thermophilus, respectively and 7.26×10-1 and 8.27×10-3 for L. bulgaricus. This study demonstrated that microencapsulation of yoghurt culture in sodium alginate is an effective technique of protecting bacterial cells against extreme drying conditions.