A comparative study of the composition of lipids associated with starch granules from various botanical sources

Understanding starch biosynthesis in potatoes for metabolic engineering to improve starch quality: A detailed review

Potato tubers accumulate substantial quantities of starch, which serves as their primary energy reserve. As the predominant component of potato tubers, starch strongly influences tuber yield, processing quality, and nutritional attributes. Potato starch is distinguished from other food starches by its unique granule morphology and compositional attributes. It possesses large, oval granules with amylose content ranging from 20 to 33 % and high phosphorus levels, which collectively determine the unique physicochemical characteristics. These physicochemical properties direct the utility of potato starch across diverse food and industrial applications. This review synthesizes current knowledge on the molecular factors controlling potato starch biosynthesis and structure-function relationships. Key topics covered are starch granule morphology, the roles and regulation of major biosynthetic enzymes, transcriptional and hormonal control, genetic engineering strategies, and opportunities to tailor starch functionality. Elucidating the contributions of different enzymes in starch biosynthesis has enabled targeted modification of potato starch composition and properties. However, realizing the full potential of this knowledge faces challenges in optimizing starch quality without compromising plant vigor and yield. Overall, integrating multi-omics datasets with advanced genetic and metabolic engineering tools can facilitate the development of elite cultivars with enhanced starch yield and tailored functionalities.

Removal of internal lipids enhances the effect of proanthocyanidins on maize starch retrogradation

Internal lipids of normal amylose (NMS) and two high amylose (HMS56, HMS72) maize starches were removed to investigate the effect of proanthocyanidins (PA) on starch short-term (1 d) and long-term (21 d) retrogradation. Removal of internal lipids decreased the degree of retrogradation in PA-starch complexes after 1 d and 21 d retrogradation. The relative crystallinity (RC) of PA-NMS, PA-HMS56 and PA-HMS72 without internal lipid complexes after short-term retrogradation decreased by 5.46 %, 6.47 % and 7.52 % when the addition of PA was 10 %, respectively, compared with corresponding samples without PA. Compared with PA-native starch complexes, PA-starch without internal lipids complexes had lower correlation length (ξ) and tended to form smaller polymeric assemblies suggesting that the size of aggregates growing within gels was decreased because more PA molecules impeded the reformation of ordered starch structures. Removal of internal lipids exposed hydrogen bonds and the cavities of amylose, promoting the interaction between PA and amylose and more formation of PA-amylose complexes, which in turn reduced amylose available for crystal nucleus formation delaying retrogradation. Overall, retrogradation could further slow down by PA after internal lipid removal, which provided a new perspective for enhancing the modification effect of PA on starch.

Formation of small-granule starch oleogels based on capillary force: Impact of starch surface lipids on lubrication performance

Starch granule oleogels were prepared and their rheological properties were precisely tuned using the capillary bridging phenomenon. The addition of a small amount of water to an oily suspension of starch granules can lead to starch granule bridging and network formation, transitioning it from a fluid-like to a gel-like state. Small-granule starches with high specific surface area and interfacial area exhibited a greater number of liquid bridges and stronger starch granules interactions, making them more prone to forming structurally stable oleogel systems. By increasing the content of water and starch granule, the starch oleogels exhibited three distinct structural states: pendular state (water ≤ 3.28 %, starch ≤ 17.85 %), pendular bridging network (water: 4.92 %, starch: 24.59 %), and capillary aggregates (water ≥ 6.56 %, starch > 24.59 %). Furthermore, the influence of starch granule surface lipids on the lubrication performance of the oleogel system was investigated. Surface roughness increased after extraction of surface lipids, and the friction coefficient also showed a significant increase. Overall, capillary suspension system can potentially be used to design novel fat food products, and our findings have established the correlation between starch granule surface properties and sensory perception in food, providing valuable insights for adjusting the oral processing characteristics of food.

Absolute Quantitative Lipidomics Reveals Different Granule-Associated Surface Lipid Roles in the Digestibility and Pasting of Waxy, Normal, and High-Amylose Rice Starches

Granule-associated surface lipids (GASLs) and internal lipids showed different lipid-amylose relationships, contents, and distributions, suggesting their differing biological origins and functions, among waxy, normal, and high-amylose rice starch. The GASL content mainly depended on the pore size, while internal lipids regulated starch biosynthesis, as indicated by correlations of internal lipids with the chain length distribution of amylopectin and amylose content. Of the 1346 lipids detected, 628, 562, and 408 differentially expressed lipids were observed between normal-waxy, high-amylose-waxy, and normal-high-amylose starch, respectively. After the removal of GASLs, the higher lysophospholipid content induced greater decreases in the peak and breakdown viscosity and swelling power, while the highest digestibility increase was found with the highest triacylglycerol content. Thus, different GASL compositions led to different digestibility, swelling, and pasting outcomes. This study sheds new light on the mechanism of the role of GASLs in the structure and properties of starch, as well as in potential modifications and amyloplast membrane development.

Reduction of starch granule surface lipids alters the physicochemical properties of crosslinked maize starch

Normal and waxy maize starches with and without removal of starch granule surface lipids (SGSLs) were crosslinked by POCl3 (0.01 %, 0.1 % and 1 %). Crosslinked starches showed lower swelling power and solubility, but higher pasting viscosity, pseudoplasticity, thixotropy, storage modulus and loss modulus. Crosslinking increased the double helical structure but decreased the crystallinity for waxy maize starch. The phosphorus content of crosslinked waxy maize starches after SGSLs removal increased, indicating SGSLs removal promoted crosslinking. SGSLs removal increased G' and G" for crosslinked waxy maize starches. SGSLs removal increased SP and solubility and decreased pasting and rheological parameters of starches. With increased POCl3 dosage, the effect of SGSLs removal on starch properties was gradually suppressed by crosslinking. Waxy and normal maize starches showed significantly different changes with crosslinking and SGSLs removal, and the presence of amylose seemed to impede the effect of crosslinking and SGSLs removal. The removal of SGSLs could extend the application of crosslinked starch in frozen foods, drinks, and canned foods as thickener and stabilizer, due to its better hydrophilicity and viscous liquid-like rheological properties. The study will assist carbohydrate chemists and food processors in developing new food products.

A study on the structural, physicochemical, rheological and thermal properties of high hydrostatic pressurized pearl millet starch

Starch in native form has limited application due to functional and physicochemical characteristics. To overcome these limitations, starch can be modified by non-thermal technologies such as high hydrostatic pressure (HHP). This study investigates high-pressure-induced gelatinization and the effect of this process on the structural, functional, morphological, pasting, thermal, physical and rheological properties of millet starch. The suspension of millet starch and water was pressurized at 200, 400 and 600 MPa for 10, 20 and 30 min to modify the starch in terms of structure, morphology, some physicochemical and rheological properties. Swelling strength and starch solubility decreased as a result of treatment with HHP. All treatments caused to increase in water holding capacity of the starch (from 0.66 % for native starch to 2.19 % for 600 MPa-30 min). Thermal analysis showed a decrease in gelatinization temperature and enthalpy of gelatinization and the pasting properties showed a decrease in the peak viscosity after HHP treatment. In addition, HHP treatment caused to increase in the hydration ability of starch by creating porosity and gaps in the granule surface and increasing the specific surface area. HHP application resulted in an increase in the peak time and pasting temperature and a decrease in breakdown and peak viscosities, final viscosity and setback viscosity in comparison with native starch of millet. The starch sample treated with 600 MPa for 30 min had the lowest syneresis and retrogradation ability. Increasing pressure and the time led to an increase in the elastic nature of the starch samples. According to the results, it is possible to increase usage area of starches in the food industry by improving its technological with HHP. This green physical technology can influence the quality parameters of starch, which can provide benefits for product machining and economic purposes.

Removal of starch granule-associated surface and channel lipids alters the properties of sodium trimetaphosphate crosslinked maize starch

Starch granule-associated surface and channel lipids (SGALs) were effectively removed from waxy maize starch (WMS) and normal maize starch (NMS), then the starches were crosslinked by different levels of sodium trimetaphosphate (STMP) (0.25 %, 0.5 %, 1 % and 2 %). The effective removal of SGALs and successful crosslinking, were evidenced by the disappearance of surface-fluorescence and channel-fluorescence of Pro-Q Diamond-stained granules, and the increased phosphorus content respectively. STMP crosslinking increased peak and final viscosity for WMS and NMS. Crosslinking at high STMP levels (0.5 %, 1 % and 2 %) transformed the starch pastes from thixotropic to anti-thixotropic. STMP crosslinking significantly decreased the tan δ values of maize starches, enhancing the elastic structure of the gel. Crosslinked maize starches without SGALs had lower breakdown than crosslinked starches at same STMP level, indicating higher tightened crosslinked starch granules after SGALs removal. Removal of SGALs increased the anti-thixotropy of crosslinked starches, facilitating the reorientation of crosslinked amylopectin/amylose molecules during shearing. Removal of SGALs increased the tan δ values from frequency sweep of WMS and NMS during STMP crosslinking, indicating the presence of surface-lipids and channel-lipids could enhance the elastic gel network structure of crosslinked maize starch.

Resistant starch: Implications of dietary inclusion on gut health and growth in pigs: a review

Starch from cereal grains, pulse grains, and tubers is a major energy substrate in swine rations constituting up to 55% of the diet. In pigs, starch digestion is initiated by salivary and then pancreatic α-amylase, and has as final step the digestion of disaccharides by the brush-border enzymes in the small intestine that produce monosaccharides (glucose) for absorption. Resistant starch (RS) is the proportion of starch that escapes the enzymatic digestion and absorption in the small intestine. The undigested starch reaches the distal small intestine and hindgut for microbial fermentation, which produces short-chain fatty acids (SCFA) for absorption. SCFA in turn, influence microbial ecology and gut health of pigs. These fermentative metabolites exert their benefits on gut health through promoting growth and proliferation of enterocytes, maintenance of intestinal integrity and thus immunity, and modulation of the microbial community in part by suppressing the growth of pathogenic bacteria while selectively enhancing beneficial microbes. Thus, RS has the potential to confer prebiotic effects and may contribute to the improvement of intestinal health in pigs during the post-weaning period. Despite these benefits to the well-being of pigs, RS has a contradictory effect due to lower energetic efficiency of fermented vs. digested starch absorption products. The varying amount and type of RS interact differently with the digestion process along the gastrointestinal tract affecting its energy efficiency and host physiological responses including feed intake, energy metabolism, and feed efficiency. Results of research indicate that the use of RS as prebiotic may improve gut health and thereby, reduce the incidence of post-weaning diarrhea (PWD) and associated mortality. This review summarizes our current knowledge on the effects of RS on microbial ecology, gut health and growth performance in pigs.

Physicochemical and multi-scale structural alterations of pea starch induced by supercritical carbon dioxide + ethanol extraction

The objective of this study was to establish the impacts of supercritical fluid extraction (SFE) processing on the physicochemical properties of pea flour and the structure of isolated pea starch. A significant (p < 0.05) increase in protein content and reduction in several pasting and thermal parameters as measured by rapid visco-analyzer and differential scanning calorimeter were observed after SFE. Additionally, SFE increased starch digestibility as determined by an in vitro starch digestion assay. An increased amylopectin content and crystallinity along with the loss of double helix content was supported by size exclusion chromatography and FT-IR data, respectively. X-ray diffraction and scanning electron microscopy showed minimal alterations of starch, by SFE, in long-range crystalline and morphological structure of starch granules, respectively. The data demonstrated SFE influenced the physicochemical and structural characteristics of pea starch. These outcomes illustrated that SFE might be a green and novel technology for starch modification.

Effects of heat-moisture treatment conditions on the physicochemical properties and digestibility of field bean starch (Vicia faba var. minor)

In the presented study, starch of two cultivars of field bean was modified via the heat-moisture treatment (HMT) at various moisture contents (15 and 30%) and temperatures (100 and 120 °C) to determine HMT effect on its physicochemical properties and digestibility. Non-modified (NM) starches showed only slight variation in properties, with the tested varieties differing only in slowly digestible starch (SDS) and resistant starch (RS) content. The HMT was shown to decrease the swelling power and amylose leaching and higher phase transition temperatures and wider gelatinization temperature ranges in all modification conditions. These effects were caused by changes in the starch structure, as evidenced by the observed the decrease in relative crystallinity. The changes were the most pronounced in the starches treated at the higher moisture level. The HMT modification modified also starch digestibility. The total content of SDS and RS in non-gelatinized HMT starches modified at 15% moisture content was higher than that determined in the starch modified at 30% moisture content. In most gelatinized HMT starches, the SDS content decreased and that of RS did not change significantly compared to the native starch. Despite modified physicochemical properties, those starches still represent a good source of resistant starch.

A current review of structure, functional properties, and industrial applications of pulse starches for value-added utilization

Pulse crops have received growing attention from the agri-food sector because they can provide advantageous health benefits and offer a promising source of starch and protein. Pea, lentil, and faba bean are the three leading pulse crops utilized for extracting protein concentrate/isolate in food industry, which simultaneously generates a rising volume of pulse starch as a co-product. Pulse starch can be fractionated from seeds using dry and wet methods. Compared with most commercial starches, pea, lentil, and faba bean starches have relatively high amylose contents, longer amylopectin branch chains, and characteristic C-type polymorphic arrangement in the granules. The described molecular and granular structures of the pulse starches impart unique functional attributes, including high final viscosity during pasting, strong gelling property, and relatively low digestibility in a granular form. Starch isolated from wrinkled pea-a high-amylose mutant of this pulse crop-possesses an even higher amylose content and longer branch chains of amylopectin than smooth pea, lentil, and faba bean starches, which make the physicochemical properties and digestibility of the former distinctively different from those of common pulse starches. The special functional properties of pulse starches promote their applications in food, feed, bioplastic and other industrial products, which can be further expanded by modifying them through chemical, physical and/or enzymatic approaches. Future research directions to increase the fractionation efficiency, improve the physicochemical properties, and enhance the industrial utilization of pulse starches have also been proposed. The comprehensive information covered in this review will be beneficial for the pulse industry to develop effective strategies to generate value from pulse starch.

Impact of Different Lipid Ligands on the Stability and IgE-Binding Capacity of the Lentil Allergen Len c 3

Previously, we isolated the lentil allergen Len c 3, belonging to the class of lipid transfer proteins, cross-reacting with the major peach allergen Pru p 3 and binding lipid ligands. In this work, the allergenic capacity of Len c 3 and effects of different lipid ligands on the protein stability and IgE-binding capacity were investigated. Impacts of pH and heat treating on ligand binding with Len c 3 were also studied. It was shown that the recombinant Len c 3 (rLen c 3) IgE-binding capacity is sensitive to heating and simulating of gastroduodenal digestion. While being heated or digested, the protein showed a considerably lower capacity to bind specific IgE in sera of allergic patients. The presence of lipid ligands increased the thermostability and resistance of rLen c 3 to digestion, but the level of these effects was dependent upon the ligand's nature. The anionic lysolipid LPPG showed the most pronounced protective effect which correlated well with experimental data on ligand binding. Thus, the Len c 3 stability and allergenic capacity can be retained in the conditions of food heat cooking and gastroduodenal digestion due to the presence of certain lipid ligands.

Identification and characterization of long non-coding RNAs regulating resistant starch biosynthesis in bread wheat (Triticum aestivum L.)

Resistant starch (RS) also known as healthy starch has shown several health benefits. Enhancing the RS through genetic modification approaches has huge commercial importance. Regulatory RNA like long non-coding RNA (lncRNA) plays an important role in gene regulation. In this study, we mined 63 transcriptome datasets of wheat belonging to 35 genotypes representing two seed developmental stages. Contrasting expression of a subset of lncRNAs in RS mutant lines compared to parent wheat variety 'C 306' signifies their probable role in RS biosynthesis. Further, lncRNA- TCONS_00130663 showed strong positive correlation (r² = 1) with LYPL gene and strong negative correlation with SBEIIb (r² = -0.94). We found TCONS_00130663 as positive regulator of LYPL gene through interaction with miR1128. Based on relative expression, in silico interaction and DSC analysis we hypothesize the dual role of TCONS_00130663 in RS type 2 and type 5. The study provides a useful resource for functional mechanism of lncRNAs.

Effect of hydrothermal modifications on properties and digestibility of grass pea starch

This study aimed to investigate functional and thermal properties and digestibility of grass pea starch, and provide information on the effect of hydrothermal modifications - annealing (ANN) and heat-moisture treatment (HMT) on the physico-chemical characteristics of the starch and digestibility, especially after processing (cooking, storage after cooking and freezing). After heat treatment, especially after cooking and storage at a temperature of -18 °C, the total content of slowly digestible starch and resistant starch in grass pea starch was high, which may indicate its great tendency for retrogradation. The HMT and ANN modifications of grass pea starch caused changes in its crystalline structure and increased integrity of its granules, which in turn resulted in a lower swelling power and amylose leaching, however this effect was more pronounced upon HMT which contributed to starch polymorphic type transformation from C to A. Despite greater resistance of granules of modified starches to swelling during cooking their suspensions, after cooking these starches were characterized by a higher predicted glycemic index than the non-modified ones. A similar content of resistant starch determined in modified and non-modified gelatinized starches stored at lowered temperatures indicates that starch modifications, HMT in particular, cause no changes in its susceptibility to retrogradation.

Impact of hydrothermal modifications on the physicochemical, morphology, crystallinity, pasting and thermal properties of acorn starch

Native acorn starch had high purity and the granules were mainly elliptical and spherical with the mean diameter of 7.32 μm. Hydrothermal modifications slightly changed the morphology. The solubility, swelling properties and amylose leaching of acorn starch were mostly influenced by Heat-moisture treatment (HMT). XRD pattern of native starch (C-type) did not change on hydrothermal modifications, but native and annealing (ANN) modified starches showed the most crystallinity. DSC results showed that the gelatinization temperatures and enthalpy of native starch were 59.9, 71.3, and 80.6 °C and -14.9 mJ/mg, respectively, and hydrothermal treatments generally increased the gelatinization temperatures. Regarding to RVA results, peak, breakdown, trough, setback, and final viscosities of native starch were 415, 143, 272, 168, and 440 RVU, respectively, and viscosity parameters of native starch were mainly more than those of hydrothermally modified starches. Generally, the intensity of the effects of hydrothermal modifications followed the order: HMT > dual modifications > ANN.

Impact of molecular structure on the physicochemical properties of starches isolated from different field pea (Pisum sativum L.) cultivars grown in Saskatchewan, Canada

The objective of this study was to determine the molecular structure and properties of recently released cultivars of field peas [CDC Golden (CDCG), Abarth (ABAR), CDC Patrick (CDCP) and CDC Amarillo (CDCA)] grown at different locations in Saskatchewan, Canada. Starch yield (on whole seed basis), apparent amylose, total lipid and specific surface area were in the range 34-37%, 38.2-42.6%, 1.07-1.38% and 0.31-0.38m2/g, respectively. The proportion of short (DP 6-12) amylopectin chains, amylopectin branching density, molecular order, crystallinity, crystalline heterogeneity, gelatinization transition temperatures, pasting temperatures, peak viscosity, extent of acid hydrolysis, and resistant starch content were higher in CDCG and ABAR. However, amylopectin long chains (DP 13-26), average chain length and thermal stability were higher in CDCP and CDCA. The results of this study showed that differences in physicochemical properties among cultivars were mainly influenced by amylopectin chain length distribution, amylopectin branching density and co-crystallization of amylose with amylopectin.

Studies on physico-chemical and cooking characteristics of rice bean varieties grown in NE region of India

Rice bean (Vigna umbellata) is grown in South and Southeast Asia, and the bean has gained importance due to its nutritional strength in terms of dietary fiber, quality protein and minerals. In current study, the nutritional and functional components, cooking and thermo-gravimetric properties of eleven rice bean varieties from NE India were investigated. Results revealed that the major nutrients among the varieties ranged as follows: 54.21-60.49% carbohydrates, 15.64-21.60% protein, 1.22-2.3% fat, 5.53-6.56% crude fibre, 3.34-3.8% ash; while the functional, anti-nutritional factors and mineral were present as 1189.32-1645.8 mg gallic acid equivalent (GAE)/100 g polyphenols, 205.38-432.14 mg/100 g phytic acid, 23.14-34.12 mg/100 g oxalate, 690.7-1589.5 mg/100 g saponins, 49.90-158.17 μg/100 g hydrocyanide, 111.51-168 calcium, 5.50-10.44 zinc, 3.72-8.37 iron. Principal component analysis revealed that varieties with higher calcium, iron and ash content had lower cooking time, swelling ratio, and cooked grain hardness. It is also revealed that varieties with higher weight loss at sixth stage in thermogravimetric graph had lower carbohydrate and higher protein content. Nagadal variety had higher fat, potassium, magnesium, calcium, sodium, iron, copper and chromium content and better cooking quality as compared to the other varieties. The study revealed that Nagadal variety was superior to other varieties with respect to mineral content, cooking and thermal properties and hence have better potential in the development of value added products.

Potato tuber expression of Arabidopsis WRINKLED1 increase triacylglycerol and membrane lipids while affecting central carbohydrate metabolism

Tuber and root crops virtually exclusively accumulate storage products in the form of carbohydrates. An exception is yellow nutsedge (Cyperus esculentus) in which tubers have the capacity to store starch and triacylglycerols (TAG) in roughly equal amounts. This suggests that a tuber crop can efficiently handle accumulation of energy dense oil. From a nutritional as well as economic aspect, it would be of interest to utilize the high yield capacity of tuber or root crops for oil accumulation similar to yellow nutsedge. The transcription factor WRINKLED1 from Arabidopsis thaliana, which in seed embryos induce fatty acid synthesis, has been shown to be a major factor for oil accumulation. WRINKLED1 was expressed in potato (Solanum tuberosum) tubers to explore whether this factor could impact tuber metabolism. This study shows that a WRINKLED1 transcription factor could induce triacylglycerol accumulation in tubers of transformed potato plants grown in field (up to 12 nmol TAG/mg dry weight, 1% of dry weight) together with a large increase in polar membrane lipids. The changes in metabolism further affected starch accumulation and composition concomitant with massive increases in sugar content.

Lipid Binding of Fresh and Stored Formulated Wheat Breads. Relationships with Dough and Bread Technological Performance

Lipid binding in fresh and stored soured started breads formulated with nonfat [sodium carboxymethylcellulose (CMC), hydroxypropylmethylcellulose (HPMC), fungal α-amylase-and fat–monoglycerides (MGL), diacetyl tartaric acid ester of mono-diglycerides (DATEM) and sodium stearoyl lactylate (SSL)] additives were determined. Results were correlated with dough and bread technological performance during breadmaking and storage. A preferential binding of the added SSL to the starch with a concomitant displacement of endogenous polar lipids from starch to gluten was observed. Monoglycerides partly bound to the starch and partial remained in the pool of free lipids with displacement of endogenous polar lipids from gluten to starch and free fractions. Addition of DATEM induced similar changes as SSL in association pattern and as MGL in polar lipid translocation. Hydrocolloids showed preferential bindings to the gluten (CMC) and to the starch (HPMC) respectively, associated to a significant displacement of endogenous neutral gluten-bounded lipids to the starchy fraction (CMC) and to a significant release of both starch- and gluten-bonded lipids (HPMC). Addition of α-amylase promoted both a release of endogenous bonded lipids and a binding of glycolipids to the starch whereas the sourer starter induced disaggregation of the starch– and gluten–lipid complexes. Suitable trends in bread lipid parameters for high fermentative power, delayed starch gelatinization, edible fresh bread and reduced bread staleness corresponded to high values of neutral lipids of bonded fractions and high total glycolipid content achieved by the incorporation of SSL and/or CMC into dough formulation.

Fatty Acids and Bioactive Lipids of Potato Cultivars: An Overview

Potato tuber is a highly nutritious, wherein genotype and environmental differences are known to exist in the shape, size and nutritional value of potatoes. Owing to its high consumption, potato could be an ideal carrier of health-promoting phytochemicals. Potato cultivars contain many bioactive lipidic compounds such as fatty acids, glycolipids, phospholipids, sterols, tocols and carotenoids, which are highly desirable in diet because of their health-promoting effects. In the scientific literature, information on the content and profile of bioactive lipidic compounds in potato cultivars are few. The concentration and stability of bioactive lipids are affected by many factors such as genotype, agronomic factors, postharvest storage, cooking and processing conditions. In this review levels and composition of bioactive lipids in terms of lipid classes, fatty acids, phytosterols, tocopherols, and caroteinoids distribution in different potato cultivars including genetically modified potato (GMP) were highlighted and discussed. In addition, factors affecting bioactive lipids levels, stability and health benefits are reviewed. In consideration of potential nutritional value, detailed knowledge on lipids of potato cultivars is of major importance.

Effects of heat treatment and moisture contents on interactions between lauric acid and starch granules

This study aimed to understand the effects of the moisture content of granular normal cornstarch (NC), heat treatment at 80 °C, and order of adding lauric acid (LA) to starch before or after the heat treatment on the physicochemical properties and digestibility of the starch. LA was added to NC priority heated with different moisture contents (10, 20, 30, 40, and 50%) or added to dried NC and then heated with different moisture contents. The hydrothermal/LA treatments increased the pasting temperature but decreased the peak viscosity of the NC. Light and scanning electron microscopy revealed that the addition of LA retarded gelatinization. The hydrothermal/LA treatments changed the X-ray pattern of the NC to a mixture of A- and V-type patterns. The thermal property and digestibility analysis showed that 40% was the optimum moisture content for the formation of the amylose-LA complex and adding LA prior to heating the NC favored the formation of slowly digestible starch.

Comparison of ambient solvent extraction methods for the analysis of fatty acids in non-starch lipids of flour and starch

BACKGROUND

Lipids are minor components of flours, but are major determinants of baking properties and end-product quality. To the best of our knowledge, there is no single solvent system currently known that efficiently extracts all non-starch lipids from all flours without the risk of chemical, mechanical or thermal damage. This paper compares nine ambient solvent systems (monophasic and biphasic) with varying polarities: Bligh and Dyer (BD); modified Bligh and Dyer using HCl (BDHCL); modified BD using NaCl (BDNaCl); methanol-chloroform-hexane (3:2:1, v/v); Hara and Radin (hexane-isopropanol, 3:2, v/v); water-saturated n-butanol; chloroform; methanol and hexane for their ability to extract total non-starch lipids (separated by lipid classes) from wheat flour (Triticum aestivum L.). Seven ambient extraction protocols were further compared for their ability to extract total non-starch lipids from three alternative samples: barley flour (Hordeum vulgare L.), maize starch (Zea mays L.) and tapioca starch (Manihot esculenta Crantz).

RESULTS

For wheat flour the original BD method and those containing HCl or NaCl tended to extract the maximum lipid and a significant correlation between lipid extraction yield (especially the glycolipids and phospholipids) and the polarity of the solvent was observed. For the wider range of samples BD and BD HCl repeatedly offered the maximum extraction yield and using pooled standardized (by sample) data from all flours, total non-starch lipid extraction yield was positively correlated with solvent polarity (r = 0.5682, P < 0.05) and water ratio in the solvent mixture (r = 0.5299, P < 0.05).

CONCLUSION

In general, BD-based methods showed better extraction yields compared to methods without the addition of water and, most interestingly, there was much greater method dependence of lipid yields in the starches when compared to the flour samples, which is due to the differences in lipid profiles between the two sample types (flours and starches).

Mechanism for starch granule ghost formation deduced from structural and enzyme digestion properties

After heating in excess water under little or no shear, starch granules do not dissolve completely but persist as highly swollen fragile forms, commonly termed granule "ghosts". The macromolecular architecture of these ghosts has not been defined, despite their importance in determining characteristic properties of starches. In this study, amylase digestion of isolated granule ghosts from maize and potato starches is used as a probe to study the mechanism of ghost formation, through microstructural, mesoscopic, and molecular scale analyses of structure before and after digestion. Digestion profiles showed that neither integral nor surface proteins/lipids were crucial for control of either ghost digestion or integrity. On the basis of the molecular composition and conformation of enzyme-resistant fractions, it was concluded that the condensed polymeric surface structure of ghost particles is mainly composed of nonordered but entangled amylopectin (and some amylose) molecules, with limited reinforcement through partially ordered enzyme-resistant structures based on amylose (for maize starch; V-type order) or amylopectin (for potato starch; B-type order). The high level of branching and large molecular size of amylopectin is proposed to be the origin for the unusual stability of a solid structure based primarily on temporary entanglements.

Increasing phosphatidylinositol (4,5) bisphosphate biosynthesis affects plant nuclear lipids and nuclear functions

In order to characterize the effects of increasing phosphatidylinositol(4,5)bisphosphate (PtdIns(4,5)P(2)) on nuclear function, we expressed the human phosphatidylinositol (4)-phosphate 5-kinase (HsPIP5K) 1α in Nicotiana tabacum (NT) cells. The HsPIP5K-expressing (HK) cells had altered nuclear lipids and nuclear functions. HK cell nuclei had 2-fold increased PIP5K activity and increased steady state PtdIns(4,5)P(2). HK nuclear lipid classes showed significant changes compared to NT (wild type) nuclear lipid classes including increased phosphatidylserine (PtdSer) and phosphatidylcholine (PtdCho) and decreased lysolipids. Lipids isolated from protoplast plasma membranes (PM) were also analyzed and compared with nuclear lipids. The lipid profiles revealed similarities and differences in the plasma membrane and nuclei from the NT and transgenic HK cell lines. A notable characteristic of nuclear lipids from both cell types is that PtdIns accounts for a higher mol% of total lipids compared to that of the protoplast PM lipids. The lipid molecular species composition of each lipid class was also analyzed for nuclei and protoplast PM samples. To determine whether expression of HsPIP5K1α affected plant nuclear functions, we compared DNA replication, histone 3 lysine 9 acetylation (H3K9ac) and phosphorylation of the retinoblastoma protein (pRb) in NT and HK cells. The HK cells had a measurable decrease in DNA replication, histone H3K9 acetylation and pRB phosphorylation.

Production of resistant starch from taro (Colocasia esculenta L. Schott) corm and determination of its effects on health by in vitro methods

The aim of the study was the production of resistant starch from taro (Colocasia esculenta L. Schott) corm and determination of its effects on health by in vitro methods. Starch was isolated from taro corms with 98% purity, and 10.4±0.5% amylose content. By application of heating, autoclaving, enzymatic debranching, retrogradation, and drying processes to taro starch for two times, resistant starch (RS) content was increased 16 fold (35.1±1.9%, dry basis). The expected glycemic index (eGI) of taro starch and taro resistant starch was determined as 60.6±0.5 and 51.9±0.9, respectively and the decrease in the glycemic index of taro resistant starch was found as statistically significant (P<0.05). The in vitro binding of bile acids by taro starch and taro resistant starch relative to cholesterol decreasing drug cholestyramine were 5.2±0.2% and 7.6±1.7%, respectively.