Starch Industry Research Articles

Changes in structural, physicochemical, and digestive properties of normal and waxy wheat starch during repeated and continuous annealing

Effects of repeated annealing treatments (8 cycles, 12 h each) or continuous annealing treatments (12–96 h) at 50 °C on structural, physicochemical, and digestive properties of normal and waxy wheat starches were investigated. Wheat starches retained the original crystalline structure of A-type after annealing. Annealing treatments increased crystallinity, short chain of amylopectin, viscosity, and gelatinization temperatures of starch. However, molecular weight, long chain of amylopectin, solubility, and swelling power of starch decreased after annealing. Additionally, annealing reduced the in vitro digestibility of wheat starches. The changes in properties of starch varied depending on starch type, normal or waxy, and annealing methods, repeated or continuous. The repeated annealing was found to be more effective in modification of normal wheat starch properties. However, continuous annealing efficiently modified properties of the waxy wheat starch. The obtained results may help in choosing appropriate applications of annealed wheat starches in the food industry.

Production, purification and applications of raw starch degrading and calcium-independent α-amylase from soil rich in extremophile

Calcium independent, raw starch hydrolyzing, acidic α-amylase (66 kDa) was synthesized by Bacillus subtilis S113 that is an aerobic, rod-shaped and Gram +ve bacteria. Purification of the enzyme was performed by HiTrap Capto Q (Ion-exchange chromatography; 19.28 fold; 22.41% yield). The purified enzyme was found stable at broad acidic pH (4–6.5) and high-temperature range (40–80 °C), that fulfilled the necessary criteria and laid the foundation to be utilized in starch saccharification industry. Kinetic studies of the enzyme revealed that Km and Vmax of the enzyme was 0.22% and 357.14 U/mg respectively. Scanning electron microscopy studies showed that the enzyme was capable of completely hydrolyzing raw wheat and potato starch, further confirming its role in the starch industry. It was found that only 7.93% of the activity was loss at 4 °C when kept for one year.

Effect of phosphorylation techniques on structural, thermal, and pasting properties of pulse starches in comparison with corn starch

The impact of three phosphorylation techniques on structural, thermal, and pasting properties of faba bean (FB) and field pea (FP) starches were investigated in comparison with regular corn (RC) starch. Phosphorylation was performed using the following three methods: a) POCl3-aqueous: 1–2% phosphorus chloride (POCl3, v/w) in aqueous slurry at 25 °C; b) STMP-semidry: 2–4% sodium trimetaphosphate/sodium tripolyphosphate (STMP/STPP 99:1. w/w) in a semidry state at 130 °C; and c) STMP-aqueous: 5–12% STMP/STPP (99:1. w/w) in aqueous slurry at 45 °C. The native and crosslinked starches were characterized using a rapid visco-analyzer (RVA), differential scanning calorimetry (DSC), X-ray diffraction (XRD), and attenuated total reflectance-Fourier transform infrared spectroscopy (ATR-FTIR). STMP-semidry showed the highest reaction efficiencies as indicated by degree of crosslinking (DC) followed by STMP-aqueous and POCl3-aqueous, while the POCl3-aqueous was the most efficient crosslinking method for altering the pasting properties (RVA) in all starches. The influence of STMP-semidry on thermal stability (DSC) was more pronounced in pulse starches, while RC starch was influenced more by POCl3-aqueous. STMP-aqueous with higher chemical concentration showed relatively lower thermal stability than STMP-semidry and POCl3-aqueous. XRD and ATR-FTIR spectra confirmed that crosslinking resulted in the loss of crystallinity. The influence of POCl3-aqueous on the disruption of crystalline structure was more pronounced in FB and FP than in RC; while STMP-aqueous had less influence on the crystalline structure of pulse starches; STMP-semidry disrupted the B-type polymorph in C-type pulse starches. This study provides a foundation for a better understanding of the structure-crosslinking-functionality relationships of pulse starches and promotes novel applications of pulse starches in food industry.

Effects of cassava variety and growth location on starch fine structure and physicochemical properties

Apparent amylose content (AAC), resistant starch (RS) content, pasting, gelatinization, retrogradation properties, and fine structural parameters amongst starches from five Thai cassava cultivars grown in two different locations were determined. Results indicated that significant differences among different varieties were found for most traits. The AAC, gelatinization onset (To) and peak temperature (Tp), the ratio of peak heights of amylopectin (hAP2/hAP1) and chain length distribution (CLD) of amylopectin fa, fb2, fb3 and average CLD (X‾) were mainly affected by genotypic effects. The peak viscosity (PV), breakdown (BD), molecular size of amylose (Rh, AM) and amylopectin (Rh, AP), average molecular size (Rh‾), the position of amylopectin peak (XAP1) and fb1 were mainly affected by environmental effects. The effects of the genotype × environment interaction were significant for BD, Rh, AM, Rh, AP, hAP2/hAP1 and fb2 values. RS was negatively correlated with the amount of amylopectin fa chains. PV and BD were affected by Rh, AM, Rh, AP, XAP1, XAP2, and the amount of fb1 chains. To and Tp were affected by XAP1, XAP2, fb1 and fb2. These results enhance our understanding of the structure-function relations of starches and are useful for the application of starch in the food industry and for breeding programs to improve the cassava starch quality.

Hybrid life cycle assessment of potato pulp valorisation in biocomposite production

Biocomposites with by-products of agro-industrial feedstock are raising industrial interest. Potato pulp, as residue of the starch industry, can be valorised in polylactide (PLA) or polyhydroxyalkanoates (PHA) systems to replace the biomass feedstock for biocomposite production. In this study, biocomposites with up to 20% by weight of potato pulp were successfully produced on industrial scale and proposed for application in pots and rigid packaging. In order to evaluate and optimize the sustainability of biocomposite supply chain, a hybrid life cycle assessment model was developed to evaluate the economic, social and environmental impacts of potato pulp valorisation in the biocomposite supply chains. The results suggested potato pulp valorisation can bring positive social-economic impacts with adverse environmental effect to both PLA and PHA biocomposite supply chains. Improving the thermal energy used in drying potato pulp has potential to achieve positive performance in GHG reduction, especially for PLA based biocomposite supply chain. Given potato pulp valorisation has other benefits, such as reduce agricultural waste and improve biodegradability. Valorising potato pulp in PLA based biocomposite supply chain can potentially facilitate the transition to a sustainable bioeconomy. It deserves further research and support from financial and political aspects.

Purification of Arabinoxylans from Corn Fiber and Preparation of Bioactive Films for Food Packaging.

Corn fiber, a by-product of the starch industry, is presently incorporated in animal feed. However, it has arabinoxylans as added-value components (besides ferulic acid) that should be valorized. In this work, the raw material, a fraction enriched in arabinoxylans from corn fiber, previously produced by alkaline extraction from corn fiber and pre-concentrated by ultrafiltration, was further purified. The use of ultrafiltration operated in diafiltration mode (dia-ultrafiltration) was evaluated for the purification of the arabinoxylans fraction. The objective was to maximize the removal of the small contaminants from the fraction and to maximize the permeability and/or the permeate flux, by selecting the relevant operating conditions involved in this process. The removal of contaminants (%) was estimated when their apparent rejection stabilized. Edible films were produced, from the resultant purified arabinoxylans fraction, using glycerol as plasticizer (30% dry basis). Additionally, films with the incorporation of ferulic acid were developed, in order to obtain barriers with antioxidant activity. The films were characterized in terms of mechanical properties, antioxidant activity and permeability to water vapor. The films prepared presented a good potential to be used as packaging for food products with low water content.

Comparison of sodium hydroxide and sodium bicarbonate pretreatment methods for characteristic and enzymatic hydrolysis of sago palm bark

ABSTRACT The present work utilized a by-product of the starch industry in Malaysia, Sago bark waste (SB), for pretreatment and enzymatic hydrolysis. SB was subjected to two types of alkaline pretreatment to assess their effect on SB characteristic, inhibitor formation, and enzymatic hydrolysis sugar yield. Dilute sodium hydroxide (DSH) and dilute sodium bicarbonate (DSB) were used for SB pretreatment. The pretreatment was carried out in a conventional heating environment (120ºC) for 10 min before the enzymatic hydrolysis step. The results showed that the treated SB by DSB resulted in higher removal of lignin (28%) compared to DSH (25%). The TGA, XRD, and SEM analysis results revealed that both types of pretreatment have slight differences. The crystallinity index (CI) for DSH and DSB was 43.2% and 41.2%, respectively. Meanwhile, HPLC results illustrated that the only inhibitor present in the pretreatment liquor is acetic acid at 0.25 mg/ml for DBS pretreatment and 0.063 mg/ml for DSH pretreatment. 229 ± 12 mg/g of total reducing sugar was found using DSH pretreatment, which is slightly higher than that one was obtained by DSB pretreatment (219 ± 16 mg/g) after enzymatic hydrolysis step. A similar observation was found on glucose and xylose yield. These results make us interfere that the diluted level of sodium bicarbonate can lead to approximately similar results of sodium hydroxide, which offer a cheap route of the pretreatment process.

Commercial viability of integrated waste treatment in cassava starch industries for targeted resource recoveries

The commercial viability of an integrated waste treatment process for converting wastewater and bagasse from a 200 t/d cassava starch facility, together with the associated cassava stalks, into bioenergy products and biofertilizer coupled with recovery of water for reuse, was assessed using Aspen Plus® simulations. The wastewater and bagasse are anaerobically digested for producing biogas that is combusted for thermal energy (Case I), or augmented with CS for combined heat and power production via steam boiler and turbo-generator while recovering biofertilizer in liquid or solid form (Cases II and III). In Case I, the biogas produced meets the thermal energy needs for starch drying in the cassava starch facility. Case II demonstrates energy self-sufficiency for the combined heat and power process and generates 28.53 MW as surplus power that is adequate for meeting power demands from the starch facility (∼2.17 MW) whereas, Case III generates only 56.5% of the biorefinery’s total power demands. In addition, liquid biofertilizer is recovered in Cases I and II while Case III allows for recovery of solid biofertilizer as well as water for reuse in the combined heat and power production, thus reducing the demand for freshwater by 66%. All three cases present potential profitable commercial investment with Net Present Values between US$ 83.4 million and 130 million, depending mainly on wastewater treatment costs and bioelectricity prices, and minimally on biofertilizer and thermal energy prices. Thus, the integration of water recovery and cassava stalks conversion into cassava waste treatment results in both economic and environmental benefits for the cassava starch industries.

Microwave-assisted Acid Pretreatment of Sago Wastewater for Fermentable Sugar Production

Sago wastewater (SWW) is one of by-products from sago starch industry. In most practice, SWW is discharged to the nearby rivers. As it contains high amount of organic compounds, usual practice of disposing the wastewater will cause a detrimental impact to the environment. The organic compounds found in SWW such as starch can be utilized as substrate for biofuel and biohydrogen fermentations. However, this starch needs to first undergo pretreatment process to breakdown its complex sugars to the simpler ones. This study aimed to investigate the effect of microwave-assisted acid pretreatment of SWW for fermentable sugar (glucose) production using sulphuric acid (H2SO4). Three parameters that influenced microwave-assisted acid pretreatment were chosen for optimization which are residence time (3-9 min), acid concentration (0.2-0.6 M) and solid loading (5-15% w/v). Faced Centered Central Composite Design (FCCCD) tool under Response Surface Methodology (RSM) in Design Expert v9.0.6.2 software was used for designing the experiments and optimization purposes. The response was the amount of glucose converted (g/L). The maximum fermentable sugar produced was 3.920 g/L, obtained at 9 minutes with 15% solid loading using 0.6 M of H2SO4. Then, the kinetic study of acid hydrolysis was performed by following the first order reaction kinetics. The rate constant of reaction obtained was 0.1684 min−1. It can be concluded that microwave-assisted acid pretreatment of SWW is able to produce high amount of fermentable sugar within a short residence time.

The Technical Efficiency of Sago and Starch Industry Cluster

The Technical Efficiency of Sago and Starch Industry Cluster

Effect of germination duration on structural and physicochemical properties of mung bean starch

Mung bean seeds were germinated at 25 °C for 12, 24, 36, 48, 60 and 72 h. Changes in structural and physicochemical properties of mung bean starch during germination were investigated. Microscopy analysis showed germination did not change the shape of starch granules, but granules isolated from germinated mung bean starch exhibited dents surface structure compared with smooth surface of native starch. The molecular weight of starch isolated from germinated mung bean was found to be smaller than that of native ones. Although germinated mung bean showed greater crystallinity than that of native sample, the germination did not change the crystalline structure type of starch (C-type). Moreover, solubility and swelling power of starch varied depending on germination duration and testing temperature. Peak viscosity and trough viscosity slightly decreased as germination prolonged to 72 h. Furthermore, starch isolated from mung bean germinated for 12 h showed greater enthalpy (ΔH) than that of starch isolated from native sample; while, ΔH decrease as germination time prolonged from 36 to 72 h. The obtained results may help in understanding the influence of germination on functional properties of mung bean starch and choosing appropriate applications to promote utilization of mung bean starch in food industry.

Starch-lipid and starch-lipid-protein complexes: A comprehensive review.

Physical interactions often occur between major food components during food processing. These interactions may involve starch, lipids, and proteins forming V-type starch-lipid complexes or ternary starch-lipid-protein complexes of larger molecular size and greater structural order. Complexes between starch and lipids have been the subject of intensive research for over half a century, whereas the study of starch-lipid-protein complexes is a relatively new field with only a limited amount of knowledge being gained so far. The formation of these complexes can significantly affect the functional and nutritional properties of finished food products in terms of flavor, texture, shelf life, and digestibility. This article provides a comprehensive review of starch-lipid and starch-lipid-protein complexes, including their classification, factors affecting their formation and structure, and preparative and analytical methods. The review also considers how complexes affect the physicochemical and functional properties of starch, including digestibility, and potential applications in the food industry.

Overexpression of an endogenous raw starch digesting mesophilic α-amylase gene in Bacillus amyloliquefaciens Z3 by in vitro methylation protocol.

Mesophilic α-amylases function effectively at low temperatures with high rates of catalysis and require less energy for starch hydrolysis. Bacillus amyloliquefaciens is an essential producer of mesophilic α-amylases. However, because of the existence of the restriction-modification system, introducing exogenous DNAs into wild-type B. amyloliquefaciens is especially tricky. α-Amylase producer B. amyloliquefaciens strain Z3 was screened and used as host for endogenous α-amylase gene expression. In vitro methylation was performed in recombinant plasmid pWB980-amyZ3. With the in vitro methylation, the transformation efficiency was increased to 0.96 × 102 colony-forming units μg-1 plasmid DNA. A positive transformant BAZ3-16 with the highest α-amylase secreting capacity was chosen for further experiments. The α-amylase activity of strain BAZ3-16 reached 288.70 ± 16.15 U mL-1 in the flask and 386.03 ± 16.25 U mL-1 in the 5-L stirred-tank fermenter, respectively. The Bacillus amyloliquefaciens Z3 expression system shows excellent genetic stability and high-level extracellular production of the target protein. Moreover, the synergistic interaction of AmyZ3 with amyloglucosidase was determined during the hydrolysis of raw starch. The hydrolysis degree reached 92.34 ± 3.41% for 100 g L-1 raw corn starch and 81.30 ± 2.92% for 100 g L-1 raw cassava starch after 24 h, respectively. Methylation of the plasmid DNA removes a substantial barrier for transformation of B. amyloliquefaciens strain Z3. Furthermore, the exceptional ability to hydrolyze starch makes α-amylase AmyZ3 and strain BAZ3-16 valuable in the starch industry. © 2020 Society of Chemical Industry.

Bambusa vulgaris starch: Characterization and technological properties

The starch industry has grown quickly, and starch production has expanded around the world because it is a very versatile ingredient, despite limits in some foodstuffs. So, this study aimed to analyze morphology, physic and chemical characteristics of the starch extracted from three different parts (bottom, middle and top) of the young bamboo culm of B. vulgaris (SB, SM, and ST, respectively). The obtained data were evaluated by analysis of variance and Scott-Knot test (p < 0.05), and no significant difference was observed between SB, SM and ST samples. The starches presented yellowish coloration (L* > 88, a* > −0.2, and b* > 9), and SEM images showed compound granules with polyhedral shapes and average diameter of 6.55 µm; apparent amylose content of 37.45%, wherein SB and SM showed characteristics of resistant starch type 2, whereas ST was more similar to normal starch. Amylopectin presented high proportion of chains with DP 13–24 and lower proportion of long chains, corroborating with A-type crystalline pattern. The absence of a shoulder in the branch chain length distribution, suggest a perfect crystalline structure, similar to starches from D. asper and B. tuldoides. DSC shows gelatinization temperatures higher than 80 °C, lower transition temperatures and the percentage of retrogradation above 44%. The results are promising to obtain slow digesting starches, although it is necessary to evaluate the starch from other bamboo species, which may have different characteristics.

Gelatinization, pasting and retrogradation properties and molecular fine structure of starches from seven cassava cultivars

Genetic diversity in the physicochemical properties and fine structures of seven cassava starches samples was studied. The apparent amylose content ranged from 24.8 to 27.6%. The whole branched starches showed significant differences in average hydrodynamic radius, ranging from 53.35 to 58.45 nm, while debranched starch exhibited differences in degrees of polymerization and height of both amylose and amylopectin peaks. The molecular size of amylose and amylopectin was positively correlated. The amount of short chains fa (6 ≤ X ≤ 12) and fb1 (13 ≤ X ≤ 24) had significant differences among the cultivars. Structure-function relation analysis indicated that the CPV and SB were mainly determined by amylopectin fine structures, BD, PTi and Tp and retrogradation properties were mainly determined by the amylose fine structure, while PTe and To were mainly affected by both amylose and amylopectin fine structures. The current findings will be helpful to improve the understanding cassava starch quality for use in industrial starch applications.

Microstructure, gelatinization and pasting properties of rice starch under acid and heat treatments

Microstructure of starch plays a vital role in the physicochemical properties. In this study, the microstructure, gelatinization and pasting properties of rice starches after acid, heat and acid-heat treatments were investigated. In our findings, molecular weight and size, amylopectin chain length distribution, degree of branching, amylose content, relative crystallinity, and hot water-solubility of rice starch were varied significantly after acid-heat treatment, showing a synergy between acid and heat. Correspondingly, acid-heat treatment markedly changed gelatinization and pasting properties of rice starch by sharply decreasing gelatinization and pasting temperatures as well as pasting viscosities. Pearson correlation analysis was performed, showing that molecular weight, size, amylopectin chain length distribution, and amylose content were significantly correlated to gelatinization temperatures, and crystallinity was remarkably correlated to gelatinization enthalpy. As for pasting properties, molecular weight and size as the major factors were substantially correlated to pasting viscosities and pasting temperature. This study provides a structure-property correlation for acid-heat treated rice starch, giving scientific basis for the application of starch in food industry.

Additional salt bridges improve the thermostability of 1,4-α-glucan branching enzyme

The 1,4-α-glucan branching enzyme from Geobacillus thermoglucosidans STB02 (GtGBE, EC 2.4.1.18) does not possess the thermostability required by modified starch industry. To increase its thermostability, a rational design strategy was used to introduce additional salt bridges into GtGBE. The strategy involved in mutation of individual residues to form “local” two-residue salt bridges. Accordingly, five of local salt bridges (Q231R-D227, Q231K-D227, T339E-K335, T339D-K335, and I571D-R569 mutants) were separately introduced into GtGBE. The half-times of these mutants at 60 °C were 17% to 51% longer than that of wild-type. Subsequently, these two-residue salt bridges were extended to form salt bridge networks (Q231R/K-D227-D131H, T339D/E-K335-I291H, and I571D-R569-R617H mutants). Among these mutants, except I571D-R569-R617H, the half-times of Q231R/K-D227-D131H, T339D/E-K335-I291H mutants at 60 °C were 15%, 17%, 21% and 17% longer than those of the corresponding two-residue salt bridges, respectively. The results showed that design and introduction of salt bridges improves enzyme thermostability in GtGBE.

Interaction and action mechanism of starch with different phenolic compounds

The interaction and action mechanism of starch with different phenolic compounds were investigated. By using scanning electron microscope, nuclear magnetic resonance, Fourier transform infra-red spectroscopy and thermogravimetric analysis, phenolic compounds exhibited the significant effects on the morphology, intensity of hydrogen bond, crystalline structure and thermal stability of starch, respectively. Furthermore, according to the analysis of molecular dynamics simulation by using short-chain glucose (SGS) as model, phenolic compounds could change the spatial configuration of starch, and had the obvious effects on the formation of hydrogen bonds (including intra- and intermolecular hydrogen bonds) and the strength of binding free energy. Meanwhile, epigallocatechin gallate possessed the strongest capacity to change the spatial configuration of starch with the consistent hydrogen bond occupancy and the lowest binding free energy. All present results suggested that phenolic compounds might be potentially utilised for improving the quality of starch in food industry.

Specific energy consumption of native starch industry in Thailand

According to the Thai Energy Efficiency Plan (EEP 2015), the government has set the target of 30% reduction in 2036 compared to the total energy consumption in 2010. The industry sector accounts for approximately 37% of the total energy consumption. Thai industries have been classified into 11 main sectors, in which food, beverage, and tobacco are the most energy-consumed sectors which consume about 35.7% of the total energy consumption. Among industries in the food, beverage, and tobacco sector, the native starch industry is the second most energy-consumed industry. Thus, the rational amount of energy saving target will be assigned to the native starch industry. Their baseline energy consumption and their potential energy saving should be known to verify the actual amount of energy savings each year. In this paper, 18 of 67 native starch plants are carefully investigated and audited to determine baseline energy consumption (BEC) and specific energy consumption (SEC) based on plant performance. Factors that effect on BEC and SEC are identified. Equations for predicting baseline BEC and SEC are developed using statistic regression approaches. It is found that SEC and BEC of the native starch industry depend on annual production quantity and annual production hours. The regression equations for predicting baseline BEC and SEC are developed and are in ±10% error range of observed data.

Influence of germination time on the morphological, morphometric, structural, and physicochemical characteristics of Esmeralda and Perla barley starch

The aim of this study was to analyzing the impact of germination time on the morphology, crystallinity, gelatinization and viscosity properties on the starch of Esmeralda and Perla barley variety. The two barley were germinated for 1 to 8 days, at 26 °C and 65% relative humidity. Micrographs showed the presence of pinholes and eroded surfaces. Starch in Esmeralda was hydrolyzed completely at 8 days of germination. Birefringence was reduced from day 4, losing molecular structuring of the crystalline area. Morphometric data: fractal dimension, area, perimeter, circularity, and roundness decreased significantly along germination time in both varieties. The entropy increased significantly, from 0.79 to 10.09 in Esmeralda and from 0.46 to 7.57 in Perla. Relative crystallinity decreased significantly in the Perla from 24.7% to 23.6%. Viscosity peaks were also significantly reduced, pasting temperature was constant in Esmeralda but in Perla was significantly reduced from 95.43 to 95.19 °C with germination, the gelatinization temperature increased significantly in the Esmeralda while in Perla it remained constant. Enthalpy decreased significantly to 75.8% and 37% in Esmeralda and Perla respectively. The study of germination impact on structural and physicochemical properties is important to identify the use of hydrolyzed starches in the food industry or others.