The quality change of fish sausage (keropok lekor) coated in sago starch-gelatine coating with
papaya seed extract (PSE) during chill storage (7°C) was determined. During storage, pH,
thiobarbituric acid value (TBA), colour, moisture, and the total plate count were evaluated. pH
of samples significantly dropped (p < 0.05) during storage, and the highest decrease was in
control sample. The moisture content in control sample had an increasing trend while that of
samples with 5 and 7% PSE coatings significantly decreased, and only a slight change for
samples with 0% PSE coating. All samples had significant increase in their TBA values during
storage. The presence of the coating provided a positive effect on the colour of the fish sausages since no significant colour changes were observed during storage. TPC of control and
coated sausage in 0, 5, and 7% PSE exceeded the recommended microbial standard after 2, 6,
8, and 4 d of storage, respectively. Overall, coating with 5% of PSE was the most effective in
retarding the quality deterioration of the fish sausages.
A split plot 3 by 3 experiment was designed to investigate the relationships among production of primary metabolites (soluble sugar and starch), secondary metabolites (total flavonoids, TF; total phenolics, TP), phenylalanine lyase (PAL) activity (EC 4.3.1.5), protein and antioxidant activity (FRAP) of three progenies of oil palm seedlings, namely Deli AVROS, Deli Yangambi and Deli URT, under three levels of CO₂ enrichment (400, 800 and 1,200 μmol·mol⁻¹) for 15 weeks of exposure. During the study, the treatment effects were solely contributed by CO₂ enrichment levels; no progenies and interaction effects were observed. As CO₂ levels increased from 400 to 1,200 μmol·mol⁻¹, the production of carbohydrate increased steadily, especially for starch more than soluble sugar. The production of total flavonoids and phenolics contents, were the highest under 1,200 and lowest at 400 μmol·mol⁻¹. It was found that PAL activity was peaked under 1,200 μmol·mol⁻¹ followed by 800 μmol·mol⁻¹ and 400 μmol·mol⁻¹. However, soluble protein was highest under 400 μmol·mol⁻¹ and lowest under 1,200 μmol·mol⁻¹. The sucrose/starch ratio, i.e., the indication of sucrose phosphate synthase actvity (EC 2.4.1.14) was found to be lowest as CO₂ concentration increased from 400 > 800 > 1,200 μmol·mol⁻¹. The antioxidant activity, as determined by the ferric reducing/antioxidant potential (FRAP) activity, increased with increasing CO₂ levels, and was significantly lower than vitamin C and α-tocopherol but higher than butylated hydroxytoluene (BHT). Correlation analysis revealed that nitrogen has a significant negative correlation with carbohydrate, secondary metabolites and FRAP activity indicating up-regulation of production of carbohydrate, secondary metabolites and antioxidant activity of oil palm seedling under elevated CO₂ was due to reduction in nitrogen content in oil palm seedling expose to high CO₂ levels.
The effect of two different CO(2) concentrations (400 and 800 μmol mol(-1)) on the photosynthesis rate, primary and secondary metabolite syntheses and the antioxidant activities of the leaves, stems and rhizomes of two Zingiber officinale varieties (Halia Bentong and Halia Bara) were assessed in an effort to compare and validate the medicinal potential of the subterranean part of the young ginger. High photosynthesis rate (10.05 μmol CO(2) m(-2)s(-1) in Halia Bara) and plant biomass (83.4 g in Halia Bentong) were observed at 800 μmol mol(-1) CO(2). Stomatal conductance decreased and water use efficiency increased with elevated CO(2) concentration. Total flavonoids (TF), total phenolics (TP), total soluble carbohydrates (TSC), starch and plant biomass increased significantly (P ≤ 0.05) in all parts of the ginger varieties under elevated CO(2) (800 μmol mol(-1)). The order of the TF and TP increment in the parts of the plant was rhizomes > stems > leaves. More specifically, Halia Bara had a greater increase of TF (2.05 mg/g dry weight) and TP (14.31 mg/g dry weight) compared to Halia Bentong (TF: 1.42 mg/g dry weight; TP: 9.11 mg/g dry weight) in average over the whole plant. Furthermore, plants with the highest rate of photosynthesis had the highest TSC and phenolics content. Significant differences between treatments and species were observed for TF and TP production. Correlation coefficient showed that TSC and TP content are positively correlated in both varieties. The antioxidant activity, as determined by the ferric reducing/antioxidant potential (FRAP) activity, increased in young ginger grown under elevated CO(2). The FRAP values for the leaves, rhizomes and stems extracts of both varieties grown under two different CO(2) concentrations (400 and 800 μmol mol(-1)) were significantly lower than those of vitamin C (3107.28 μmol Fe (II)/g) and α-tocopherol (953 μmol Fe (II)/g), but higher than that of BHT (74.31 μmol Fe (II)/g). These results indicate that the plant biomass, primary and secondary metabolite synthesis, and following that, antioxidant activities of Malaysian young ginger varieties can be enhanced through controlled environment (CE) and CO(2) enrichment.
Potatoes are usually stored under low temperatures for sprout prevention and to ensure their continuous supply. Low
temperature sweetening in potato is the major temperature related disorder being faced by the growers and is also
known to be associated with variety specific storage temperature. The present study aimed at identifying the appropriate
storage temperature for the premium potato variety Lady Rosetta with special reference to the changes in its quality
attributes, that is weight loss, total sugars, starch, ascorbic acids, total phenolic contents, radical scavenging activity,
enzymatic activities and potato chip color. The selected potato variety was stored under different temperature (5, 15 and
25o
C) regimes to identify appropriate storage temperature. Our results showed significant variations in the tested quality
attributes in response to different storage temperatures. Storage at 5o
C maintained tuber dormancy up to 126 days,
however, found associated with increased sugar accumulation (2.32 g/100 g), rapid starch depletion (13.25 g/100 g) and
poor post processing performance (L-value, 52.00). In contrast, potato storage at 15o
C retained lower sugar contents
(1.33 g/100g) and superior chip color (L-value, 59.33) till the end of storage. However, they were found associated with
the increased polyphenol oxidase (38.47 U/g f.w) and peroxidase (15.25 U/100 g f.w) activities as compare to those
potatoes stored at 5o
C during the same storage period. Storage life of potato tubers at 25o
C was significantly reduced
due to dormancy break on 84th day and subsequent starch degradation (15.29 g/100 g) increased sugar accumulation
(1.32 g/100 g) and increased polyphenol oxidase (79.89 U/g f.w) and peroxidase activities (40.69 U/100 g f.w). Our
results showed that potato variety Lady
This study was driven by the stringent environmental legislation concerning the consumption and utilization of eco-friendly materials. Within this context, this paper aimed to examine the characteristics of starch and fibres from the Dioscorea hispida tuber plant to explore their potential as renewable materials. The extraction of the Dioscorea hispida starch and Dioscorea hispida fibres was carried out and the chemical composition, physical, thermal, morphological properties, and crystallinity were studied. The chemical composition investigations revealed that the Dioscorea hispida starch (DHS) has a low moisture t (9.45%) and starch content (37.62%) compared to cassava, corn, sugar palm, and arrowroot starches. Meanwhile, the Dioscorea hispida fibres (DHF) are significantly low in hemicellulose (4.36%), cellulose (5.63%), and lignin (2.79%) compared to cassava, corn hull and sugar palm. In this investigation the chemical, physical, morphological and thermal properties of the Dioscorea hispida fibre and Dioscorea hispida starch were examined by chemical composition investigation, scanning electron microscopy (SEM), particle size distribution, thermogravimetric analysis (TGA), X-ray powder diffraction (XRD), and Fourier transform infrared (FTIR), respectively. It was found that Dioscorea hispida waste is promising alternative biomass and sustainable material with excellent potential as a renewable filler material for food packaging applications.
This study examines the effects of varying the concentrations of sorbitol (S) and glycerol (G) on the physical, morphological, thermal, and mechanical properties of Dioscorea hispida, starch-based films. In this context, the films of Dioscorea hispida starch were developed using solution casting technique with glycerol (G), sorbitol (S), and a mixture of sorbitol-glycerol (SG) as plasticizers at the ratios of 0, 30, 45, and 60 wt%. The films' moisture contents were increased when increasing the plasticizer contents. The tensile strengths were decreased, but elongations at break were increased; 7.38%-11.54% for G-plasticized films, 10.17%-15.76% for S-plasticized films, and 14.41%- 16.10% for SG-plasticized films with increasing plasticizer concentrations of the film samples. Varying plasticizer concentrations exhibited a minor effect on the S-plasticized film's thermal properties. Significant decrement in the glass transition temperatures of Dioscorea hispida starch films was observed when the plasticizer contents were raised from 30% to 60%. Significantly, the present work has shown that plasticized Dioscorea hispida starch can be considered a promising biopolymer for the applications of biodegradable films.
The production of pullulanase by Bacillus flavothermus KWF-1 in batch and fed batch culture were compared using 2L bioreactor. In batch culture, 0.0803 U/mL of pullulanase activity with specific activity of 0.0213 U/mg was produced by controlling the agitation speed and temperature at 200 rpm and 50 °C, respectively. Fed batch production was studied by feeding the culture with different sago starch concentrations in various feeding modes for enhanced pullulanase production. Exponential feeding mode at dilution rate of 0.01/h was the preeminent strategy for enhanced pullulanase production of 0.1710 U/mL with specific activity of 0.066 U/mg. It had shown an increment of pullulanase production and specific activity by 2.1 and 3.1-fold, respectively when compared to batch culture. Increment of pullulanase activity in exponential feeding mode improved hydrolyzation of sago starch into maltotriose and panose by 4.5 and 2.5-fold respectively compared to batch system.
Haruan or Channa striatus is source of protein that is widely consumed in the region and its extract
is well known for having medical values. It is of great advantage if this product could be taken
orally rather than by injection because the oral route of drug delivery is still preferred by the vast
majority of patients. However protein and peptides can be denatured or degraded by the acidic pH
of the stomach and the presence of endogenous enzymes. In order to protect or prevent digestion
and degradation of the protein in the stomach and to ensure the protein reaches the gastro
intestinal (GI) tract, Carboxymethyl Starch (CMS) nanogel system was developed using electron
irradiation method. However stability of HTE during the irradiation process needed to be studied
before being developed further. In this study, the HTE was irradiated using electron beams. Its
stability was analysed in terms of physical and chemical changes by looking at colour difference,
melting point by using Differential Scanning Calorimetry (DSC) and molecular bonds by using
Fourier Transform Infrared (FTIR) respectively. The results of this study were that no apparent
colour difference was observed with HTE before and after irradiation. These observations were
supported by the FTIR and DSC results that showed that there were no changes in molecular bonds
and melting point, compared between no irradiation and irradiation HTE during electron
irradiation up to 10 kGy. Statistically the test showed no significant difference at p < 0.005 between
melting temperatures.
Ozone-oxidised starches were prepared from the native starches isolated from white and red cocoyam, and white and yellow yam cultivars. The native and oxidised starches were evaluated for functional, thermal and molecular properties. The correlations between the amount of reacted ozone and carbonyl and carboxyl contents of the starches were positive, as ozone generation time (OGT) increased. Significant differences were obtained in terms of swelling power, solubility, pasting properties and textural properties of the native starches upon oxidation. The DSC data showed lower transition temperatures and enthalpies for retrograded gels compared to the gelatinized gels of the same starch types. The native starches showed CB-type XRD patterns while the oxidised starches resembled the CA-type pattern. As amylose content increased, amylopectin contents of the starches decreased upon oxidation. Similarly, an increase in Mw values were observed with a corresponding decrease in Mn values upon oxidation.
The effect of heat treatment below the gelatinization temperature on the susceptibility of corn, mung bean, sago, and potato starches towards granular starch hydrolysis (35°C) was investigated. Starches were hydrolyzed in granular state and after heat treatment (50°C for 30 min) by using granular starch hydrolyzing enzyme for 24 h. Hydrolyzed heat-treated starches showed a significant increase in the percentage of dextrose equivalent compared to native starches, respectively, with corn 53% to 56%, mung bean 36% to 47%, sago 15% to 26%, and potato 12% to 15%. Scanning electron microscopy micrographs showed the presence of more porous granules and surface erosion in heat-treated starch compared to native starch. X-ray analysis showed no changes but with sharper peaks for all the starches, suggested that hydrolysis occurred on the amorphous region. The amylose content and swelling power of heat-treated starches was markedly altered after hydrolysis. Evidently, this enzyme was able to hydrolyze granular starches and heat treatment before hydrolysis significantly increased the degree of hydrolysis.
Radiation processing has been employed successfully for value addition of food and agricultural products. Preliminary studies were undertaken to evaluate the changes induced by ionizing radiation (up to 30 kGy), in the form of gamma irradiation and electron beam irradiation, on some quality attributes and nutritive values of nutraceutically valued lotus seeds. Significant loss in seed firmness was recorded between control and irradiated seeds, irrespective of radiation source. Similarly, the specific viscosity of irradiated lotus seeds decreased significantly up to a dose of 7.5 kGy. Starch increased after exposure to gamma or electron beam irradiation, whereas the total phenolic contents were decreased. Gamma irradiation revealed an enhancement in protein, while the electron beam showed a decrease. Partial oxidation of the seeds during radiation treatments might have occurred as evidenced from the decomposition profiles (thermogravimetry) during heating. It is evident that ionizing radiation brought about significant and variable changes in the quality and nutritive values of lotus seed. Further exploration of this technology for safety and quality is warranted.
The effects of oxidation by ozone gas on some physicochemical and functional properties of starch (corn, sago, and tapioca) were investigated. Starch in dry powder form was exposed to ozone for 10 min at different ozone generation times (OGTs). Carboxyl and carbonyl contents increased markedly in all starches with increasing OGTs. Oxidation significantly decreased the swelling power of oxidized sago and tapioca starches but increased that of oxidized corn starch. The solubility of tapioca starch decreased and sago starch increased after oxidation. However, there was an insignificant changed in the solubility of oxidized corn starch. Intrinsic viscosity [eta] of all oxidized starches decreased significantly, except for tapioca starch oxidized at 5 min OGT. Pasting properties of the oxidized starches followed different trends as OGTs increased. These results show that under similar conditions of ozone treatment, the extent of starch oxidation varies among different types of starch.
Edible films were prepared from a mixture of partially hydrolyzed sago starch and alginate (SA). Lemongrass oil (0.1% to 0.4%, v/w) and glycerol (0% and 20%, w/w) were incorporated in the films to act as natural antimicrobial agent and plasticizer, respectively. The films were characterized for antimicrobial activity, water vapor permeability (WVP), tensile strength (TS), percent elongation at break (%E), and water solubility (WS). Fourier transform infrared (FTIR) spectroscopy was conducted to determine functional group interactions between the matrix and lemongrass oil. The zone of inhibition was increased significantly (P < 0.05) by addition of lemongrass oil at all levels in the presence and the absence of glycerol. This indicates that the film containing lemongrass oil was effective against Escherichia coli O157:H7 at all levels. In the absence of glycerol, the tensile strength of film decreased as the oil content increased, but there was no significant (P > 0.05) difference in percent elongation. The percent elongation at break and WVP values for film with 20% glycerol was found to be increased significantly (P < 0.05) with an increase in lemongrass oil content. Addition of lemongrass oil did not have any interaction with the functional groups of films as measured by FTIR.
Composite sago starch-based system was developed and characterized with the aim to find an alternative to gelatin in the processing of pharmaceutical capsules. Dually modified (Hydrolyzed-Hydroxypropylated) sago starches were combined with κ-carrageenan (0.25, 0.5, 0.75, and 1%). The rheological properties of the proposed composite system were measured and compared with gelatin as reference material. Results show that combination of HHSS12 (Hydrolysed-hydroxypropylated sago starch at 12h) with 0.5% κ-carrageenan was comparable to gelatin rheological behavior in pharmaceutical capsule processing. The solution viscosity at 50 °C and sol-gel transition of the proposed composite system were comparable to those of gelatin. The viscoelastic moduli (G' and G") for the proposed system were lower than those of gelatin. These results illustrate that by manipulation of the constituents of sago starch-based composite system, a suitable alternative to gelatin can be produced with comparable properties and this could find potential application in pharmaceutical capsule industry.
Direct conversion of gelatinized sago starch into kojic acid by Aspergillus flavus strain having amylolytic enzymes was carried out at two different scales of submerged batch fermentation in a 250-mL shake flask and in a 50-L stirred-tank fermentor. For comparison, fermentations were also carried out using glucose and glucose hydrolyzate from enzymic hydrolysis of sago starch as carbon sources. During kojic acid fermentation of starch, starch was first hydrolyzed to glucose by the action of alpha-amylase and glucoamylase during active growth phase. The glucose remaining during the production phase (non-growing phase) was then converted to kojic acid. Kojic acid production (23.5 g/L) using 100 g/L sago starch in a shake flask was comparable to fermentation of glucose (31.5 g/L) and glucose hydrolyzate (27.9 g/L) but in the 50-L fermentor was greatly reduced due to non-optimal aeration conditions. Kojic acid production using glucose was higher in the 50-L fermentor than in the shake flask.
A study of the kinetics and performance of solvent-yielding batch fermentation of individual sugars and their mixture derived from enzymic hydrolysis of sago starch by Clostridium acetobutylicum showed that the use of 30 g/L gelatinized sago starch as the sole carbon source produced 11.2 g/L total solvent, i.e. 1.5-2 times more than with pure maltose or glucose used as carbon sources. Enzymic pretreatment of gelatinized sago starch yielding maltose and glucose hydrolyzates prior to the fermentation did not improve solvent production as compared to direct fermentation of gelatinized sago starch. The solvent yield of direct gelatinized sago starch fermentation depended on the activity and stability of amylolytic enzymes produced during the fermentation. The pH optima for alpha-amylase and glucoamylase were found to be at 5.3 and 4.0-4.4, respectively. alpha-Amylase showed a broad pH stability profile, retaining more than 80% of its maximum activity at pH 3.0-8.0 after a 1-d incubation at 37 degrees C. Since C. acetobutylicum alpha-amylase has a high activity and stability at low pH, this strain can potentially be employed in a one-step direct solvent-yielding fermentation of sago starch. However, the C. acetobutylicum glucoamylase was only stable at pH 4-5, maintaining more than 90% of its maximum activity after a 1-d incubation at 37 degrees C.
This review article highlights the thermal behaviors of selected starches that were studied using differential scanning calorimetery (DSC) with data shown in various research publications. The starches of sago, potato, sweet potato, cassava, yam, and corn are included in this overview. Our examinations indicate that thermal properties are highly affected by the type of starch, its amylose/amylopectin content, and the presence of other food ingredients such as sugar, sodium chloride, water, milk, hydrocolloids, and meat. When the heating temperatures of the starches were increased, the DSC measurements also showed an increase in the temperatures of the gelatinization (onset [To ], peak [Tp ], and conclusion [Tc ]). This may be attributed to the differences in the degree of crystallinity of the starch, which provides structural stability and makes the granule more resistant to gelatinization.
Antibacterial effect of modified sago starch-alginate edible film incorporating lemongrass oil at various concentrations was studied. Edible films were prepared from a mixture of modified sago starch and alginate. Lemongrass oil (0.1 - 0.4%, v/w) and glycerol (0 and 20%, w/w) were incorporated in the films to act as natural antimicrobial agent and plasticizer, respectively. The films were characterized for antibacterial activity against food pathogenic bacteria such as Escherichia coli O157:H7, Salmonella Enteritidis and Staphylococcus aureus. The edible film exhibited antibacterial activity against Escherichia coli O157:H7 and Salmonella Enteritidis by using agar diffusion assay method. For films tested against Escherichia coli O157:H7, the zone of inhibition increased significantly (p < 0.05) with addition of lemongrass oil at all levels both in the presence and absence of glycerol. The films also significantly (p < 0.05) inhibited the growth of Salmonella enteritidis only with 0.4% lemongrass oil (in the presence and absence of glycerol). However, the films containing lemongrass oil did not show any inhibition effect on Staphylococcus aureus.
Dielectric properties study is important in understanding the interaction between materials within electromagnetic field. By knowing and understanding the dielectric properties of materials, an efficient and effective microwave heating process and products can be designed. In this study, the dielectric properties of several encapsulation wall materials were measured using open-ended coaxial probe method. This method was selected due to its simplicity and high accuracy. All materials exhibited similar behavior. The result inferred that β-cyclodextrin (BC), starch (S), Arabic (GA) and maltodextrin (M) with various dextrose equivalent exhibited effective encapsulation wall materials in microwave encapsulation-drying technique owing to loss tangent values which were higher than 0.1 at general application frequency of 2.45 GHz. Thus, these were found to be suitable as wall material to encapsulate the selected core material in this microwave encapsulation-drying method. On contrary, sodium caseinate showed an ineffective wall material to be used in microwave encapsulation-drying. The differences in the values of dielectric constant, loss factor and loss tangent were found to be contributed by frequency, composition and bulk density.
This paper provides a comprehensive analysis of the dielectric and physicochemical properties of the porous hydroxyapatite/cornstarch (HAp/Cs) composites in a new perspective. The porous composites have been characterized via SEM, FTIR, XRD and dielectric spectroscopy. The dielectric permittivity spectra were obtained in Ku-band (12.4-18.0 GHz) and it was correlated with the physicochemical properties of the porous HAp/Cs. Porous HAp/Cs composites exhibits low ε' and negative ε″, which influenced by the microstructural morphology, interaction between Hap and Cs, as well as crystalline features due to the various proportion of the HAp/Cs. The physicochemical effect of the composites results in the dielectric polarization and energy loss. This phenomenon indicates the presence of the three obvious relaxation responses in the ε' spectrum (13.2-14.0, 15.2-16.0, and 16.6-17.4 GHz) and the negative behaviours in the ε″ spectrum. The relationships between physicochemical and dielectric properties of the porous composite facilitate the development of the non-destructive microwave evaluation test for the porous composite.