Physicochemical Properties of Common and Tartary Buckwheat Starch

Physicochemical properties of starch of three common (Fagopyrum esculentum) and three tartary (F. tataricum) buckwheat varieties from Shanxi Province, China, were compared. Starch color, especially b*, differed greatly between tartary (7.99–9.57) and common (1.97–2.42) buckwheat, indicating that removal of yellow pigments from tartary buckwheat flour may be problematic during starch isolation. Starch swelling volume in water of reference wheat starch (2.8% solids and 92.5°C) was 20.1 mL; for the three common buckwheat starches it was 27.4–28.0 mL; and for the three tartary buckwheat starches it was 26.5–30.8 mL. Peak gelatinization temperature (T_p) in water was 63.7°C for wheat starch, 66.3–68.8°C for common buckwheat and 68.8–70.8°C for tartary buckwheat. T_p of all samples was similarly delayed (by 4.0–4.8°C) by 1% NaCl. Enthalpy of gelatinization (ΔH) was higher for all six buckwheat starches than it was for wheat starch. However, one common buckwheat sample had significantly lower ΔH than the others. Starch pasting profiles, measured by a Rapid Visco-Analyzer, were characteristic and similar for all six buckwheat starches, and very different from the reference wheat starch. A comparison of pasting characteristics of common and tartary buckwheat starches to wheat starch indicated similar peak viscosity, higher hot paste viscosity, higher cool paste viscosity, smaller effect of NaCl on peak viscosity, and higher resistance to shear thinning. Texture profile analysis of starch gels showed significantly greater hardness for all buckwheat samples when compared to wheat starch.     

Physicochemical Properties of Normal and Waxy Job's Tears (Coix lachryma-jobi L.) Starch

Physicochemical properties of starches from eight coix (Coix lachrymajobi L.) accessions were investigated. There was considerable variation in most measured traits, generally corresponding to the separation into waxy and normal amylose types. The amylose contents of five normal coix ranged from 15.9 to 25.8%, and those of three waxy coix were 0.7–1.1%. Swelling power of waxy coix starches varied between 28.6 and 41.0 g/g, generally higher than waxy maize. Normal coix starches had significantly higher gelatinization peak temperature (T_p) than the normal maize, 71.9–75.5°C. The T_p of waxy coix starches was 71.1–71.4°C, similar to waxy maize. Rapid Visco-Analyser (RVA) pasting profiles of normal coix showed little variation and closely matched the normal maize starch profile. Pasting profiles of waxy coix showed more variation and had lower peak viscosities than waxy maize starch. Waxy coix starches formed very weak gels, while the gel hardness of normal coix starches was 11.4–31.1 g. Amylose content was the main factor controlling differences in starch properties of the coix starches.     

Fractionation and reconstitution experiments provide insight into the role of gluten and starch interactions in pasta quality

Commercial durum wheat (Triticum durum desf.) semolina was fractionated into starch, gluten, and water extractables. Starch surface proteins and surface lipids were removed, and two starches with manipulated granule size distributions were produced to influence starch properties, affecting its interaction with other semolina components. Reconstituted spaghetti was made with untreated (control) or treated starches. The pasta made from the starting semolina material had lower cooking time and was of lower quality than the samples made from reconstituted material. This was not due to changes in gluten properties as a result of the first step of the fractionation process. For the reconstituted samples, starch interaction behavior was not changed after surface protein or surface lipid removal. Starch surface properties thus do not influence the starch interaction behavior, indicating that starch-gluten interaction in raw (uncooked) pasta is mainly due to physical inclusion. All reconstituted pasta samples also had generally the same cooking quality. It was concluded that the small changes in starch gelatinization behavior, caused by the above-mentioned starch modifications, are of little importance for pasta quality.     

Effect of Source and Proportion of Waxy Starches on Pasta Cooking Quality

Starches from the endosperm of three types of total‐waxy cereals (bread wheat, maize, and barley) were used in reconstitution studies of durum wheat semolinas to investigate the effect of waxy starch on pasta cooking quality. The chemical composition and the pasting and gelatinization properties of the starches used in this study were evaluated to define the functional properties of each waxy starch. The rheological properties of dough semolinas were evaluated by small‐scale mixograph. Spaghetti was prepared using a small‐scale pasta extruder and its cooking quality was assessed using a texture analyzer. Cooked pasta firmness, resilience, and stickiness were measured. The substitution of semolina starch with waxy starches from different sources changed the functional properties of dough and their pasta quality. A decrease in firmness was detected in all the semolinas reconstituted with waxy starches. An increase in stickiness was found when semolinas with waxy starch from wheat were evaluated. No improvement in pasta quality should be expected if the waxy character is introduced in durum wheat.     

Thermal Modifications of Starch During High‐Temperature Drying of Pasta

Changes in starch at the molecular level during high‐temperature (HT) drying of pasta were studied with differential scanning calorimetry (DSC). Pasta was manufactured from durum wheat semolina into the shape of spaghetti on a pilot‐plant installation. The HT phase (100°C) was applied at relatively high (27 g/100 g, wb), intermediate (20 g/100 g), and low (15 g/100 g) product moisture, respectively. Spaghetti dried at 55°C served as reference samples. The changes in the thermal properties of starch during drying were dependent on the drying conditions. The gelatinization enthalpy of pasta dried at 55°C was reduced by 30% during drying, which indicates a partial melting of the starch crystallites. With the beginning of the HT phase, the gelatinization enthalpy increased to final values that were close to or higher than those of freshly extruded pasta. In general, HT drying of pasta induced a broadening of the gelatinization range. Starch crystallinity remained unchanged during extrusion and drying at HT. Based on a state diagram of starch and on DSC measurements of pasta during drying, it is hypothesized that HT drying favors molecular rearrangements of starch polymers at the double helical level.     

Functional Properties of Commingled Rice‐Cultivar Lots

Commingling of rice cultivars commonly occurs during harvest, drying, and storage operations. Because different cultivars often have different functional properties, there is a need to study the impact of commingling on these properties. Two long‐grain hybrid (H) cultivars, CL XL745 and CL XL729, and two long‐grain pureline (P) cultivars, CL 151 and Wells, were used to prepare H/P, H/H, and P/P commingles in various proportions. Gelatinization and pasting properties of all individual lots and commingled samples were measured. When two cultivar lots with different onset gelatinization temperatures (T_os) were commingled, the T_o of the commingled sample was similar to the T_o of that cultivar in the commingle with the lower T_o. T_ps, T_cs, and ΔHs of commingled samples generally increased or decreased according to the mass percentages of the cultivars in the samples. Peak, breakdown, and final viscosities of commingled samples also varied according to the mass percentages of the cultivars in the commingled samples. These findings are intended to help make decisions regarding cultivar commingling and to optimize process conditions and product characteristics, given the gelatinization and pasting properties of individual‐cultivar lots.     

Quality Characteristics of Waxy Hexaploid Wheat (Triticum aestivum L.): Properties of Starch Gelatinization and Retrogradation

The viscoelastic properties and molecular structure of the starch isolated from waxy (amylose-free) hexaploid wheat (WHW) (Triticum aestivum L.) were examined. WHW starch generally had lower gelatinization onset temperature, peak viscosity, and setback than the starch isolated from normal hexaploid wheat (NHW). Differential scanning calorimetry (DSC) showed that WHW starch had higher transition temperatures (T_o, T_p, and T_c) and enthalpy (ΔH) than NHW starch. However, when compared on the basis of amylopectin (AP) content, ΔH of WHW starch was almost statistically identical to that of its parental varieties. Typical A-type X-ray diffraction patterns were observed for the starches of WHW and its parental varieties. Somewhat higher crystallinity was indicated for WHW starch. WHW starch was also characterized by having greater retrogradation resistance. The high-performance size-exclusion chromatography (HPSEC) of amylopectin showed that each amylopectin yielded two fractions after debranching. Although WHW amylopectin had somewhat long B chains, little difference was observed in the ratio of Fr.III/ Fr.II between WHW and its parental varieties.     

Effects of Mixing Conditions on Pasta Dough Development and Biochemical Changes

Mixing of commercial durum wheat semolina with water was performed under different conditions in a Brabender micromixer equipped with pastamaking shafts. Semolina filling of the mixing chamber was 30.4–42.9% (v/v), shaft speed was 10–110 rpm, temperature was 10–40°C, and hydration level was 47–52.5% (db). The blend of water and semolina evolved from individualized hydrated particles (HP) to a dough product (DP) as a function of these conditions. Torque values (T) and the specific mechanical energies (SME) were recorded during mixing as a function of time. Terms from these curves were defined to characterize the mixing process: t_o (starting time of dough development), t_d (time to reach the maximum dough consistency), T_m (mean torque value after dough development), and SME_f (total energy applied to the dough during mixing). Transformation of HP into DP and the mixing temperature were the main parameters affecting t_o, t_d, T_m, and SME_f. Protein aggregate distribution was measured by size-exclusion HPLC, protein solubility in 0.01N acetic acid, free -SH content, soluble arabinoxylans, reducing sugars, ferulic acid, carotenoid content, and oxidase activities to characterize the biochemical changes that occurred during pasta dough formation. DP was characterized by lower amounts of insoluble glutenin aggregates, lower protein solubility in dilute acetic acid, lower free -SH content, ferulic acid, carotenoid content, and lower oxidoreductase activities as compared to HP. Once the dough was developed, the effects of mixing speed, temperature, or hydration level on the biochemical composition of the blend were null or low compared to the modifications that were observed when the blends changed from HP to DP. The t_o and SME_f were the most significant parameters in characterizing the pasta dough mixing process in relation to biochemical changes.     

Fractionation and reconstitution experiments provide insight into the role of starch gelatinization and pasting properties in pasta quality

Commercial durum wheat semolina was fractionated into protein, starch, water-extractable, and sludge fractions. The starch fraction was hydroxypropylated, annealed, or cross-linked to change its gelatinization and pasting properties. Spaghettis were made by reconstitution of the fractions, and their quality was assessed. Hydroxypropylated starches were detrimental for cooked pasta quality. Cross-linked starches made the reconstituted pasta firmer and even brittle when the degree of cross-linking was too high. These results indicate that starch properties play a role in pasta quality, although the gluten remains very important as an ultrastructure agent. It was concluded that, given a certain gluten ultrastructure, starch water uptake and gel properties and/or its interference with or breakdown of the continuous gluten network during cooking determine pasta quality.     

Starch Characteristics of Waxy and Nonwaxy Tetraploid (Triticum turgidum L. var. durum) Wheats

Manufacture of pasta products is paramount for durum wheat (Triticum turgidum L. var. durum). The recent development of waxy durum wheat containing starch with essentially 100% amylopectin may provide new food processing applications and present opportunities for value‐added crop production. This investigation was conducted to determine differences in some chemical and functional properties of waxy durum starch. Starch was isolated from two waxy endosperm lines and four nonwaxy cultivars of durum wheat. One of the waxy lines (WX‐1) was a full waxy durum wheat whereas the other line (WX‐0) was heterogeneous, producing both waxy and nonwaxy seed. Effects on starch swelling, solubility, pasting, gelatinization, and retrogradation were examined. The full waxy starch had four times more swelling power than the nonwaxy durum starches at 95°C, and was also more soluble at three of the four temperatures used. Starch pasting occurred earlier and peak viscosities were greater for starches from both waxy lines than for the nonwaxy starches, but their slurries were less stable with continued stirring and heating. Greater energy was required to melt gelatinized waxy starch gels, but no differences were found in either refrigerated storage or freeze‐thaw retrogradation, as determined by differential scanning calorimetry. The results of this investigation showed some significant differences in the starch properties of the waxy durum wheat lines compared to the nonwaxy durum wheats.     

REVIEW: An Overview on Fusarium Mycotoxins in the Durum Wheat Pasta Production Chain

Fusarium head blight (FHB) is one of the major diseases of wheat (both common and durum wheat) caused by various fungi including Microdochium nivale and different Fusarium species. Most of the Fusarium species associated with FHB (mainly F. graminearum, F. culmorum and F. sporotrichioides), under favourable environmental conditions, can produce various toxic secondary metabolites (mycotoxins) that can contaminate grains. The major Fusarium mycotoxins that can occur in wheat and derived products are deoxynivalenol, nivalenol, T‐2 and HT‐2 toxins, and zearalenone. Processing has generally significant effects on the levels of mycotoxins in the final products. Deoxynivalenol is typically concentrated in the bran coat which is removed in the production of semolina; consequently, a consistent reduction of deoxynivalenol levels has been observed during each of the processing steps, from raw durum wheat to pasta production. To allow monitoring programs and protect consumers' health, several analytical methods have been developed for Fusarium mycotoxins, based on chromatographic or immunometric techniques. The European Union has established maximum permitted levels for some Fusarium mycotoxins in cereals and cereal‐based products (including unprocessed durum wheat, bran, wheat flour, and pasta). Recommendations for the prevention and reduction of Fusarium mycotoxins contamination in cereals based on identification of critical risk factors and crop management strategies have been published by the Codex Alimentarius and the European Commission.     

Effect of Sucrose on Glass Transition,Gelatinization, and Retrogradation of Wheat Starch

Differential scanning calorimetry (DSC) was used to study the effect of sucrose on wheat starch glass transition, gelatinization, and retrogradation. As the ratio of sucrose to starch increased from 0.25:1 to 1:1, the glass transition temperature (T_g, T_g′) and ice melting enthalpy (ΔH_ice) of wheat starch‐sucrose mixtures (with total moistures of 40–60%) were decreased to a range of −7 to −20°C and increased to a range of 29.4 to 413.4 J/g of starch, respectively, in comparison with wheat starch with no sucrose. The T_g′ of the wheat starch‐sucrose mixtures was sensitive to the amount of added sucrose, and detection was possible only under conditions of excess total moisture of >40%. The peak temperature (T_m) and enthalpy value (ΔH_G) for gelatinization of starch‐sucrose systems within the total moisture range of 40–60% were increased with increasing sucrose and were greater at lower total moisture levels. The T_g′ of the starch‐sucrose system increased during storage. In particular, the significant shift in T_g′ ranged between 15 and 18°C for a 1:1 starch‐sucrose system (total moisture 50%) after one week of storage at various temperatures (4, 32, and 40°C). At 40% total moisture, samples with sucrose stored at 4, 32, and 40°C for four weeks had higher retrogradation enthalpy (ΔH) values than a sample with no sucrose. At 50 and 60% total moisture, there were small increases in ΔH values at storage temperature of 4°C, whereas recrystallization of samples with sucrose stored at 32 and 40°C decreased. The peak temperature (T_p), peak width (δT), and enthalpy (ΔH) for the retrogradation endotherm of wheat starch‐sucrose systems (1:0.25, 1:0.5, and 1:1) at the same total moisture and storage temperature showed notable differences with the ratio of added sucrose. In addition, T_p increased at the higher storage temperature, while δT increased at the lower storage temperature. This suggests that the recrystallization of the wheat starch‐sucrose system at various storage temperatures can be interpreted in terms of δT and T_p.     

Physical and Molecular Characterization of Millet Starches

This study investigated the physical and molecular starch characteristics of four Canadian‐grown millet species: pearl, foxtail, proso, and finger millet. The millet starch granules ranged from about 2.5 to 24 μm in size and were mainly polygonal with a few spherical ones. Their amylose contents ranged from 28.6 to 33.9%, with finger and pearl millets having much more of long amylose chains than short amylose chains compared with foxtail and proso millets. Starches also differed in the molecular structure of their branched amylose, with finger and pearl millets having longer glucan chains between branch points. The enthalpy of gelatinization of starch granules ranged from 11.8 to 13.2 J/g, and the enthalpy of melting of the retrograded starches ranged from 2.2 to 5.9 J/g. The onset temperature of gelatinization (T_o) of the starches ranged from 62.8 to 70.6°C. Addition of iodine vapor to the granular starches showed significant (P < 0.05) differences in the ratio of the absorbance to scattering coefficient (K/S) values, indicating differences in the rigidity of the glucan chains present in the granules. Starches with short amylose chains exhibited higher K/S values. Iodine vapor addition resulted in altered X‐ray diffractogram peak intensities. The study suggested differences in the structure and granular architecture of the millet starches.     

Thermal Properties of Starch in Corn Variants Isolated After Chemical Mutagenesis of Inbred Line B73

The starch from eight ethyl methanesulfonate (EMS) treated M4 families of the corn (Zea mays L.) inbred line B73 was analyzed using differential scanning calorimetry (DSC), a Rapid Visco Analyser (RVA), a texture analyzer (TA), and scanning electron microscopy (SEM) coupled with image analysis. The eight families were chosen from 144 families previously selected for having starch with unusual DSC parameters. Apparent amylose contents of the starch from the eight families generally were lower than that of the control. According to DSC, starches from mutagenized families tended to have lower onset temperature (T₀) of gelatinization, enthalpy (ΔH) of gelatinization, and peak height index (PHI), but broader gelatinization range (R) than the B73 control. Their values for ΔH and percentage of retrograzdation (%R) were clustered around that of the control. Pasting properties from the RVA of the starches from the M4 families also were clustered around those of the control B73 starch, except for the setback values which were lower than B73 for M4 starches. Gel firmness values, as measured by TA, of all the M4 starches were generally lower than that of the B73 starch at storage treatments of one day at 25°C or seven days at 4°C. The stickiness of the gels of the M4 starches tended to be greater than that of B73 after seven days of storage at 4°C. These observations were consistent with the lower apparent amylose values for the M4 starches. SEM and image analysis data revealed no differences among the treatments in granule size and shape. Possibly, EMS treatment altered the genes, affecting internal structure of the starch granules. Starch from the mutagenized families likely had lower bonding forces among molecules and fewer long chains in the amylopectin molecules than did B73.     

A Fast,Simple, and Reliable Method to Predict Pasta Yellowness

Pasta yellowness depends on the semolina carotenoid content, carotenoid degradation by lipoxygenase (LOX), and pasta processing conditions. In breeding programs, early generation lines are selected for high grain yellow pigment content with the intent to improve pasta color. This approach has been successful in increasing the grain yellow pigment of Canadian durum wheat in the last few decades. In recent years, however, a weak relationship between pasta yellowness (b*) as measured by a Minolta spectrophotometer and semolina yellow pigment content (r = 0.19–0.52) was noted in the Canadian durum wheat lines. Thus, total semolina yellow pigment content cannot effectively predict the yellowness of its pasta product. Therefore, a fast and simple method was developed to predict pasta yellowness by measuring semolina dough sheet color at different time intervals after sheeting (0.5, 2.0, and 24 hr). Spaghettis were processed from the semolina samples at two drying temperature cycles (70 and 90°C). There were significant correlations between dough sheet b* values at all three times and spaghetti b* values at both drying temperatures (r = 0.87–0.94). Semolina dough sheet can be easily prepared in 15 min and requires only 30 g of material. Shortly after sheeting (30 min), dough sheet b* values can be used to predict pasta yellowness without producing the end product (involving mixing, extrusion, and drying). In this study, we also found that dough sheet b* values increased significantly with time over the sampling intervals after sheeting for those breeding lines with superior pasta color. DNA analysis revealed that all those lines lacked the Lpx‐B1.1 duplication.     

Physical Properties and Enzymatic Digestibility of Phosphorylated ae,wx, and Normal Maize Starch Prepared at Different pH Levels

Phosphorylated starches were prepared with sodium tripolyphosphate (STPP) at pH 6, 8, and 10 from waxy (wx, 3.3% amylose), normal (22.4% amylose), and two high-amylose (ae, 47 and 66% amylose) maize starches. After phosphorylation, the gelatinization peak temperature (T_p) decreased and pasting peak viscosity (PV) increased for all the starches except wx, which showed a slight increase in gelatinization temperature. There was a substantial effect of phosphorylation pH on paste viscosity. More crosslinking was found in ae starches with phosphorylation at pH 10. Sodium ions apparently decreased PV of all the phosphorylated starches while only slightly affecting PV of native starches. Phosphorylation increased swelling power of some of the starches, with maximum swelling power at phosphorylation pH 8 and minimum at pH 10. Maximum swelling power for wx starch after preparation was at pH 8 and minimum at pH 6. After phosphorylation, the clarity and freeze-thaw stability of all the starches was greatly increased compared with the native starches. Phosphorylation increased digestibility of ae starches but had little effect on wx and normal starches. After phosphorylation, the adhesiveness, springiness, and cohesiveness of all starch gels generally increased, the hardness of 47% ae and wx starches increased, and that of normal starches decreased. Enthalpy of gelatinization decreased after phosphorylation with the greatest decrease observed for ae starches. When the phosphorylation pH increased from 6 to 10, the brightness (L*) of all the phosphorylated starches decreased, while a* and b* of all the phosphorylated starch increased. Scanning electron micrographs showed some erosion on the surface of starch granules after phosphorylation.     

Quantitative Genetic Basis of Gelatinization Temperature of Rice

Gelatinization temperature of rice starch plays an important role in grain quality. We mapped eight loci responsible for the gelatinization parameters of rice: onset temperature (T_o), peak temperature (T_p), conclusion temperature (T_c) and enthalpy (ΔH) using a population of 242 recombinant inbred lines (RIL). Eight quantitative trait loci (QTL) were mapped onto the chromosome regions where starch‐synthesis related genes are located. The Wx gene (granule‐bound starch synthase [GBSS]), and the region of chromosome 11 played major roles in gelatinization trait determination; and other loci were starch‐branching enzyme (SBE) genes that modify the two major loci by epistasis. High‐level interactions were also detected indicating a trans mode of action of the genes. The genetic basis for these parameters was consistent with the relationship between the thermal properties and the structure of the starch granule. This information can be helpful for the improvement of starch‐producing crops, including the improvement of rice grain quality, both for food and industrial uses.     

Characterization of Durum Wheat Semolina by Means of a Rapid Shear‐Based Method

A rapid shear‐based test (the GlutoPeak test, recently proposed by Brabender) was used to investigate gluten aggregation properties of durum wheat semolina and to relate them to pasta cooking behavior. Thirty semolina samples were characterized by means of the conventional approaches used for pasta‐quality prediction (protein content, gluten index, and alveographic indices). All samples were also analyzed by the GlutoPeak test, obtaining three parameters: maximum peak torque, maximum peak time, and area under the peak. The GlutoPeak indices were significantly correlated with protein content, gluten index, and W alveographic parameter. The cooking quality of pasta obtained from the 30 semolina samples was evaluated by sensory analysis in terms of stickiness, bulkiness, firmness, and overall quality. The GlutoPeak indices were significantly correlated with the sensorial parameters. In comparison with the alveographic test, which is presently the most used rheological approach for semolina characterization, GlutoPeak analysis presents some advantages represented by a smaller amount of sample (9 g), a shorter time (less than 5 min), and the possibility that untrained analysts can carry it out. In addition, following testing with larger sample numbers, the GlutoPeak test has the potential to be used instead of the gluten index as a rapid and reliable approach for medium‐quality semolina characterization.     

拔节期追氮对鲜食糯玉米粉糊化和热力学特性的影响

以苏玉糯1号、苏玉糯5号和渝糯7号为材料,研究了拔节期追氮量（N 0、150和300 kg/hm2）对鲜食糯玉米粉糊化和热力学特性的影响。结果表明,随着拔节期追氮量的增加,峰值黏度和崩解值下降,糊化温度升高,而谷值黏度、终值黏度和回复值呈先降后升趋势; 热力学特征参数中,回生值、终值温度、糊化范围和峰值指数受拔节期追氮量影响较小。原样品热焓值和回生后样品热焓值均表现为随着拔节期追氮量的增加呈先降后升趋势。糊化和热力学特征值对拔节期追氮量的响应不同品种间存在差异。鲜食糯玉米粉的理化特性存在显著的基因型差异,峰值黏度以苏玉糯5号最高,苏玉糯1号最低; 峰值温度苏玉糯1号和苏玉糯5号无显著差异,但均高于渝糯7号; 热焓值、回生值、糊化范围和峰值指数不同品种间相对稳定。相关分析表明,峰值黏度与原样品热焓值和峰值指数呈显著正相关; 崩解值与糊化温度及转变温度,回生值与淀粉的终值黏度和回复值呈显著负相关。在本试验条件下,拔节期追氮总体上使糯玉米食用品质降低,其中以苏玉糯5号在不追氮处理下的糊化和热力学特性较优,即峰值黏度、崩解值和热焓值较高,回生值较低。     

Thermal Properties of Starch from 62 Exotic Maize (Zea mays L.) Lines Grown in Two Locations

The variability in thermal properties among 62 S₃ lines derived from a high-yielding exotic corn (Zea mays) population, Antigua 1 (PI 484990), was evaluated by differential scanning calorimetry (DSC). The S₃ lines were grown in Puerto Rico (1990–1991) and Georgia (1994). Separate single-kernel starch extractions for five kernels (five replicates) from each line grown in each location were performed, and the starch was analyzed. The DSC values reported included gelatinization onset (T_oG), range (R_G), enthalpy (ΔH_G), and peak height index (PHI) and retrogradation onset (T_oR), range (R_R), enthalpy (ΔH_R), and percent retrogradation (%R) (an indication of the stability of gelatinized starch after storing at 4°C for 7 days). Significant differences (P < 0.05) were found among the 62 lines of Antigua 1 for T_oG, R_G, and PHI and highly significant differences (P < 0.01) were found for ΔH_G. The starches from plants grown in Georgia (1994) had significantly (P < 0.05) greater T_oG, ΔH_G, and PHI but a significantly lower R_G than those from Puerto Rico (1990–1991). These data suggest that the starch from plants grown in Georgia (1994) might have a greater degree of crystallinity than that from Puerto Rico (1990–1991). None of the retrogradation values were significantly different among starches of the 62 lines of Antigua 1 and the starches from plants grown in the two locations.