Lilia Collado - Academia.edu (original) (raw)

Papers by Lilia Collado

Research paper thumbnail of Comparative Study of High Amylose and Low Amylose Rice for the Preparation of Puto, a Filipino Fermented Rice Cake

Food Science and Biotechnology, 1992

Research paper thumbnail of Some small-scale techniques for measuring noodle quality

Research paper thumbnail of Physicochemical properties of mung bean starches in different Korean varieties and their gel textures

Food Science and Biotechnology, 2012

Research paper thumbnail of Identification and utilization of genetic variation in sweetpotato starch properties

Research paper thumbnail of pH dependent amylase activity and pasting properties of sweet potato flour and wheat-Sweet potato composite flours

Differences in pasting profiles (measured with a Rapid Visco-Analyser, RVA) of sweet potato flour... more Differences in pasting profiles (measured with a Rapid Visco-Analyser, RVA) of sweet potato flour (SPF) of 4 different genotypes were due mainly to differences in diastatic activity. Furthermore, at 25% (w/w) substitution of SPF with wheat flour, the pasting of the composite flour was greatly altered compared to 100% wheat flour. Addition of 25% (w/w) CL-946-25 flour, an SPF with high amylase activity, decreased the peak viscosity (PV) by 60%, but addition of 25% CL-1489-89, an SPF with minimal amylase activity, lowered the peak viscosity by only 24%. This sensitivity of wheat starch to sweet potato amylases is a major constraint to its use in composite flours. Composite flours pasted over a pH range of 3 to 11 showed marked differences in the pasting parameters. At pH 4 and at pH 10-11, there were no significant differences in the pasting profiles of the SPF composite flours as compared to all-wheat flour, due to amylase inhibition under extreme pH conditions. Composite flours with added mercuric chloride (20 ppm) (an amylase inhibitor which did not alter the pH of the flour slurry) showed no significant differences in pasting profiles compared to composite flours to which various acidulants were added. Thus food additives such as ascorbic acid, HCl and lactic acid can be used in some cases to reduce the effect of amylases. Where end-product quality would be adversely affected by low pH, screening for sweet potato varieties with minimal amylase activity would be appropriate and can be done using the RVA. Screening for this purpose should be done at around pH 6 where the sweet potato amylase activity is at the optimum.link_to_subscribed_fulltex

Research paper thumbnail of Utilization of Isolated Soy Protein for the Enrichment of Puto, a Lactic Acid Fermented Rice Cake of the Philippines

Food Science and Biotechnology, 1993

Research paper thumbnail of Characterization of alkaline-cooked quality protein maize as raw material for noodle processing

Quality protein maize (QPM) possesses high tryptophan and lysine contents and may be processed in... more Quality protein maize (QPM) possesses high tryptophan and lysine contents and may be processed into food products with improved protein content. Alkaline cooking enhances the functional and nutritional properties of corn and can be employed as an intermediate step in processing corn products. In this study, we aimed to evaluate the textural, sensorial, and cooking characteristics of noodles prepared from two white QPM varieties (SWQ 11 and SWQ 15) with different kernel characteristics. The QPM varieties had different starch, protein, fiber, and fat contents. The QPM varieties were nixtamalized and the resulting masa was used for noodle production. The QPM noodles had lower cooking yields (2.5%) than yellow alkaline noodles (YAN) from wheat (3.8%) and corn starch noodles (CSN) (5%). Cooking loss of the SWQ 11 noodles (3.9 %) was lower than SWQ 15 noodles (6.8 %) and YAN (6.9 %). CSN had the greatest cooking loss (15%). Among texture parameters, hardness and cutting stress values of t...

Research paper thumbnail of Starch Properties and Functionalities

Properties, Analysis And Applications, 2003

Cereal grains store energy in the form of starch. The proportion of starch in the grain is genera... more Cereal grains store energy in the form of starch. The proportion of starch in the grain is generally between 60 and 75% by weight (Hoseney 1986). It makes up about 90% of milled-rice dry weight (Juliano 1985) and 72% of the maize kernel dry weight (Boyer and Shannon 1987) and is the primary product obtained from wet milling of maize. In maize, most starch occurs in the endosperm, but significant amounts are also found in the embryo, bran, and tip cap (Watson 1984; Boyer and Shannon 1987). Flour or meal functionality in foods thus depends significantly on this major component. Aside from its nutritive value, the significance of starch is appreciated more for the physical properties it imparts to our foods. Mutations that alter the levels of starch, the amylose and amylopectin ratio, and starch structure in the maize endosperm have been identified (Shannon and Garwood 1984;Wasserman et al. 1995). The availability of these mutants has also enabled study of the correlation between the molecular structure and functional properties of starches. These mutations lead to starches with new properties and functionalities and greatly expand the range of possible food and industrial applications. With the increasing power of genetic engineering techniques and a closer integration with physical property testing, there is now considerable global interest in developing highly targeted starch structure variants with specific functional-

Research paper thumbnail of Adhesion, cohesion, and friction estimated from combining cutting and peeling test results for thin noodle sheets

Journal of food science, 2015

The aim of this study was to estimate the adhesive and cohesive fracture energies, and frictional... more The aim of this study was to estimate the adhesive and cohesive fracture energies, and frictional characteristics of 7 types of cooked starch and flour sheets and combine these into a model framework for textural analysis. Cutting tests with wires of diameter 0.30 to 0.89 mm were performed with and without lubrication. Plots of the work done, normalized to the area cut by the wire, showed that this to be linearly related to wire diameter irrespective of lubrication. The oil had little impact on the intercept of these plots, giving cohesive fracture energy (Gc ) ranges for these foods between 6.8 and 32.5 J/m(2) . However, lubrication had a strong influence on the slope of the plots. From a comparison of the slopes for lubricated versus unlubricated tests, the kinetic coefficient of friction μkcould be calculated. Values for μk between 0.007 and 0.521 for different foods were obtained. Peeling tests were performed by lifting sheets vertically away from a fresh mica surface. The adhes...

Research paper thumbnail of Nutritional Enhancement of Asian Wheat Products by Starch and Protein Supplementation

Food for Health in the Pacific Rim

... STONE, LA and LORENZ, K. 1984. The starch of Amaranthus - physico-chemical properties and fun... more ... STONE, LA and LORENZ, K. 1984. The starch of Amaranthus - physico-chemical properties and functional characteristics. StarchlStiirke 36, 232-237. ... Starch properties of the sweet potato, diploid Ipomeu frzmu (HBK) Don and tetraploid hybrids. StarchlStarke 43, 133-138. ...

Research paper thumbnail of Rice and Starch-Based Noodles

Science, Technology, and Processing, 2010

Research paper thumbnail of Physical properties and utilization of sweet potato starch and flour

published_or_final_versionBotanyDoctoralDoctor of Philosoph

Research paper thumbnail of Functional, digestibility, and antioxidant properties of brown and polished rice flour from traditional and new-improved varieties grown in Sri Lanka

Starch - Stärke, 2011

Sri Lankan traditional and improved rice varieties were processed into brown and polished rice fl... more Sri Lankan traditional and improved rice varieties were processed into brown and polished rice flours. Samples were analyzed for AM, protein, lipid, total phenolic content, and antioxidant activity. Gelatinization and retrogradation properties were observed in the Rapid Visco Analyzer (RVA) and DSC. The AM content of the samples was high to intermediate (20 to 26%) except for one which was low (17%). Brown rice flour (BRF) samples had lower swelling power, lower RVA viscoamylograph profile, lower gel hardness, lower gelatinization enthalpy but higher gelatinization peak temperature and lower melting enthalpies of its retrograded AP relative to its corresponding polished rice flour (PRF) samples. The BRF showed a lower decrease in peak viscosity in the RVA viscoamylograph as compared to its PRF when treated with a-amylase indicating inhibition potential. The traditional rice varieties had 68 to 86% higher total phenolic content (TPC) and 86 to 90% antioxidant activity in the BRF samples as compared to the improved varieties. A study on the antioxidant profile of the brown rice of the traditional rice varieties is being undertaken to explore their value as functional foods.

Research paper thumbnail of Effect of parboiling on the formation of resistant starch, digestibility and functional properties of rice flour from different varieties grown in Sri Lanka

Journal of the Science of Food and Agriculture, 2013

BACKGROUND: Hydrothermal treatment used in parboiling could induce formation of novel starch prop... more BACKGROUND: Hydrothermal treatment used in parboiling could induce formation of novel starch properties having potential food applications. In the current work, functional, digestible and retrogradation properties of flour from non-parboiled and steamed parboiled six rice varieties with high amylose content of around 30% but differing in length and width ratio were investigated and compared. RESULTS: The parboiling process reduced swelling volume and amylose leaching in all tested varieties. Among the varieties studied, the resistant starch content ranged from 1.6% in AT 306 to 0.46% in BG 357. Parboiling reduced the resistant starch content in AT 306 by about 50%, but it did not significantly affect the resistant starch content of the other varieties. The amylose-lipid complex remained unchanged after parboiling. Amylopectin retrogradation was not observed in parboiled rice. Amylose retrogradation was not seen except for AT 306. Pasting behaviour of parboiled rice flours showed high pasting stability and low setback. Flours were more susceptible to enzymatic hydrolysis after parboiling. Partial gelatinisation during parboiling was sufficient to produce grains with excellent milling quality showing a head rice recovery that ranged from 98% to 100% among the varieties studied. CONCLUSION: Degree of gelatinisation is the most important factor that determines the high head rice recovery. High pasting stability and low setback of flour of parboiled rice indicate some potential food applications.

Research paper thumbnail of Bihon-Type Noodles from Heat-Moisture-Treated Sweet Potato Starch

Journal of Food Science, 2001

Sweet potato starch (SPS) has limited uses in the Philippines, but modification of its properties... more Sweet potato starch (SPS) has limited uses in the Philippines, but modification of its properties may make it more suitable for use in traditional products that normally use other types of starch. Heat-moisture treatment was applied to native SPS (HMTSPS), which was used as a substrate and composite with maize starch (MS) to produce bihon-type starch noodles. Preliminary quality scoring showed that acceptability scores of raw starch noodles, plain boiled, and sautéed noodles made from 100% HMTSPS and 50% HMTSPS:50% MS were not significantly different from the commercial bihon. However, consumer testing is recommended to further validate acceptability of the sweet potato for bihon.

Research paper thumbnail of Genetic Variation in the Physical Properties of Sweet Potato Starch

Journal of Agricultural and Food Chemistry, 1999

Sweet potato starch, prepared from 44 genotypes adapted to Philippine conditions, showed wide var... more Sweet potato starch, prepared from 44 genotypes adapted to Philippine conditions, showed wide variation and distinctly different pasting profiles in Rapid Visco-Analyzer (RVA) analysis at 11% and 7% starch concentration. At 11% starch concentration, the pasting profiles were type A, characterized by high to moderate peak with a major breakdown and low cold paste viscosity. At 7%, the pasting profile was generally type C, characterized by the absence of a distinct peak with none to very slight breakdown and high cold paste viscosity. However, differentiation among genotypes was better achieved from RVA pasting profiles at 11% starch concentration. Peak viscosity (PV) and hot paste viscosity (HPV) at 11% starch paste concentration had significant negative correlation with amylose content. PV, HPV, and setback ratio were significantly correlated to adhesiveness of the starch gel. Sweet potato starch generally had high swelling volume but low solubilities at 92.5°C.

Research paper thumbnail of Accurate Estimation of Sweetpotato Amylase Activity by Flour Viscosity Analysis

Journal of Agricultural and Food Chemistry, 1999

Sweetpotato flour (SPF), prepared from 44 genotypes adapted to Philippine conditions, showed wide... more Sweetpotato flour (SPF), prepared from 44 genotypes adapted to Philippine conditions, showed wide variation in Rapid Visco-Analyzer (RVA) pasting characteristics due to its variation in composition and endogenous amylase activity. The RVA pasting parameters of peak viscosity determined in water (PV1) and that determined in 0.05 mM AgNO 3 (used as an amylase inhibitor) (PV2) were successfully used to estimate R-amylase activity. The correlation of the ratio (PV2-PV1)/PV1 to R-amylase activity was 0.96 (p < 0.01, N) 44). Swelling volume measurements were not found to be suitable for prediction of R-amylase activity.

Research paper thumbnail of Heat-moisture treatment effects on sweetpotato starches differing in amylose content

Food Chemistry, 1999

Sweetpotato starch from two genotypes, Taiwan (15.2% amylose) and 93-006 (28.5% amylose), were ex... more Sweetpotato starch from two genotypes, Taiwan (15.2% amylose) and 93-006 (28.5% amylose), were exposed to heat-moisture treatment (HMT) of 25% moisture at 110 C for various exposure times at`as-is' (pH 6.5±6.7) and alkaline pH (pH 10) conditions. In both starch samples at`as-is' pH, there was a shift from a Type A pasting pro®le (characterized by a high to moderate pasting peak, major breakdown after holding time at 95 C and low cold paste viscosity) to a Type C pasting pro®le (characterized by lack of a pasting peak and no breakdown, with high cold paste viscosity in 93-006; and a slight breakdown in Taiwan). With HMT at pH 10, the pasting peak viscosity was increased and low hot paste viscosities and high cold paste viscosities were observed. Under both pH conditions after HMT, there were marked increases in gelatinization temperatures and broadening of the DSC gelatinization endotherms, and considerable decreases in swelling volume and solubilities. Gel textures of HMT starch samples appeared to be related to amylose content. Taiwan starch gel had a marked increase in hardness and adhesiveness, while that of 93-006 did not show signi®cant dierences in hardness after HMT. Both starch samples showed a marked reduction in resilience, indicating a shift from a long stringy nature to short paste consistency. Starch gels exposed to HMT under alkaline conditions showed a high degree of syneresis.

Research paper thumbnail of Genetic Variation in Color of Sweetpotato Flour Related to Its Use in Wheat-Based Composite Flour Products

Cereal Chemistry, 1997

Cereal Chem. 74(5):681-686 Sweetpotato flours vary widely in color depending on genotype, and whe... more Cereal Chem. 74(5):681-686 Sweetpotato flours vary widely in color depending on genotype, and when used in wheat-based composite flours, they will impart characteristic colors which may be favorable or unfavorable for particular food products. Sweetpotato flour (SPF) was prepared from 44 genotypes and analyzed for proximate composition and biochemical properties. The Hunter Color L*, a*, b* values of the dry SPF and their modified Pekar slicks (PS) with water and with alkali were measured. Polyphenol oxidase activity, α-amylase activity, and total sugar were significantly correlated to L* values of dry SPF and of their PS tests with water and with alkali. The yellow pigment level was significantly correlated to the yellowness (b*) of the dry flour and of the PS test with water, but less correlated to b* of the PS test with alkaline. The results indicated a complex biochemical basis to SPF color, and no single biochemical factor examined was adequate to predict the color of a food product made from SPF. However, the PS color parameters were highly correlated with the color of dough sheets for white-salted and yellow-alkaline noodles made from wheat and sweetpotato composite flour (75:25). Thus, the simple modified PS test could be used in screening of genotypes for color stability and suitability for a specific end-use. SPF genotypes conferred a wide range of colors on composite flour dough preparations. Some colors, particularly the range of greens and bright orange, may be useful in specialty product development.

Research paper thumbnail of Production of Bihon-type Noodles from Maize Starch Differing in Amylose Content

Cereal Chemistry Journal, 2004

Cereal Chem. 81(4):475-480 Maize starches extracted from selected maize cultivars with 0.2-60.8% ... more Cereal Chem. 81(4):475-480 Maize starches extracted from selected maize cultivars with 0.2-60.8% amylose contents were used to produce bihon-type noodles. Starch dough using a pregelatinized starch binder was prepared and extruded through a laboratory-scale extruder simulating the traditional process of making bihon in the Philippines. The normal maize starches with amylose content of ≈28% were successfully used for bihon-type noodle production, but waxy maize starches with 0.2-3.8% amylose content and high-amylose maize starches with 40.0-60.8% amylose content failed to produce bihontype noodles. Viscoamylograph profile parameters and swelling volume are significantly correlated to amylose content of maize starch samples evaluated. These physicochemical properties may be used to indicate that the starch samples at normal amylose levels may be used for bihon-type noodles. Starch noodles produced in the laboratory were not significantly different in terms of either cooking quality or textural properties from two commercially produced maize noodle samples, except for adhesiveness. The laboratory process and fabricated extruder can be used to produce bihon-type noodles.

Research paper thumbnail of Comparative Study of High Amylose and Low Amylose Rice for the Preparation of Puto, a Filipino Fermented Rice Cake

Food Science and Biotechnology, 1992

Research paper thumbnail of Some small-scale techniques for measuring noodle quality

Research paper thumbnail of Physicochemical properties of mung bean starches in different Korean varieties and their gel textures

Food Science and Biotechnology, 2012

Research paper thumbnail of Identification and utilization of genetic variation in sweetpotato starch properties

Research paper thumbnail of pH dependent amylase activity and pasting properties of sweet potato flour and wheat-Sweet potato composite flours

Differences in pasting profiles (measured with a Rapid Visco-Analyser, RVA) of sweet potato flour... more Differences in pasting profiles (measured with a Rapid Visco-Analyser, RVA) of sweet potato flour (SPF) of 4 different genotypes were due mainly to differences in diastatic activity. Furthermore, at 25% (w/w) substitution of SPF with wheat flour, the pasting of the composite flour was greatly altered compared to 100% wheat flour. Addition of 25% (w/w) CL-946-25 flour, an SPF with high amylase activity, decreased the peak viscosity (PV) by 60%, but addition of 25% CL-1489-89, an SPF with minimal amylase activity, lowered the peak viscosity by only 24%. This sensitivity of wheat starch to sweet potato amylases is a major constraint to its use in composite flours. Composite flours pasted over a pH range of 3 to 11 showed marked differences in the pasting parameters. At pH 4 and at pH 10-11, there were no significant differences in the pasting profiles of the SPF composite flours as compared to all-wheat flour, due to amylase inhibition under extreme pH conditions. Composite flours with added mercuric chloride (20 ppm) (an amylase inhibitor which did not alter the pH of the flour slurry) showed no significant differences in pasting profiles compared to composite flours to which various acidulants were added. Thus food additives such as ascorbic acid, HCl and lactic acid can be used in some cases to reduce the effect of amylases. Where end-product quality would be adversely affected by low pH, screening for sweet potato varieties with minimal amylase activity would be appropriate and can be done using the RVA. Screening for this purpose should be done at around pH 6 where the sweet potato amylase activity is at the optimum.link_to_subscribed_fulltex

Research paper thumbnail of Utilization of Isolated Soy Protein for the Enrichment of Puto, a Lactic Acid Fermented Rice Cake of the Philippines

Food Science and Biotechnology, 1993

Research paper thumbnail of Characterization of alkaline-cooked quality protein maize as raw material for noodle processing

Quality protein maize (QPM) possesses high tryptophan and lysine contents and may be processed in... more Quality protein maize (QPM) possesses high tryptophan and lysine contents and may be processed into food products with improved protein content. Alkaline cooking enhances the functional and nutritional properties of corn and can be employed as an intermediate step in processing corn products. In this study, we aimed to evaluate the textural, sensorial, and cooking characteristics of noodles prepared from two white QPM varieties (SWQ 11 and SWQ 15) with different kernel characteristics. The QPM varieties had different starch, protein, fiber, and fat contents. The QPM varieties were nixtamalized and the resulting masa was used for noodle production. The QPM noodles had lower cooking yields (2.5%) than yellow alkaline noodles (YAN) from wheat (3.8%) and corn starch noodles (CSN) (5%). Cooking loss of the SWQ 11 noodles (3.9 %) was lower than SWQ 15 noodles (6.8 %) and YAN (6.9 %). CSN had the greatest cooking loss (15%). Among texture parameters, hardness and cutting stress values of t...

Research paper thumbnail of Starch Properties and Functionalities

Properties, Analysis And Applications, 2003

Cereal grains store energy in the form of starch. The proportion of starch in the grain is genera... more Cereal grains store energy in the form of starch. The proportion of starch in the grain is generally between 60 and 75% by weight (Hoseney 1986). It makes up about 90% of milled-rice dry weight (Juliano 1985) and 72% of the maize kernel dry weight (Boyer and Shannon 1987) and is the primary product obtained from wet milling of maize. In maize, most starch occurs in the endosperm, but significant amounts are also found in the embryo, bran, and tip cap (Watson 1984; Boyer and Shannon 1987). Flour or meal functionality in foods thus depends significantly on this major component. Aside from its nutritive value, the significance of starch is appreciated more for the physical properties it imparts to our foods. Mutations that alter the levels of starch, the amylose and amylopectin ratio, and starch structure in the maize endosperm have been identified (Shannon and Garwood 1984;Wasserman et al. 1995). The availability of these mutants has also enabled study of the correlation between the molecular structure and functional properties of starches. These mutations lead to starches with new properties and functionalities and greatly expand the range of possible food and industrial applications. With the increasing power of genetic engineering techniques and a closer integration with physical property testing, there is now considerable global interest in developing highly targeted starch structure variants with specific functional-

Research paper thumbnail of Adhesion, cohesion, and friction estimated from combining cutting and peeling test results for thin noodle sheets

Journal of food science, 2015

The aim of this study was to estimate the adhesive and cohesive fracture energies, and frictional... more The aim of this study was to estimate the adhesive and cohesive fracture energies, and frictional characteristics of 7 types of cooked starch and flour sheets and combine these into a model framework for textural analysis. Cutting tests with wires of diameter 0.30 to 0.89 mm were performed with and without lubrication. Plots of the work done, normalized to the area cut by the wire, showed that this to be linearly related to wire diameter irrespective of lubrication. The oil had little impact on the intercept of these plots, giving cohesive fracture energy (Gc ) ranges for these foods between 6.8 and 32.5 J/m(2) . However, lubrication had a strong influence on the slope of the plots. From a comparison of the slopes for lubricated versus unlubricated tests, the kinetic coefficient of friction μkcould be calculated. Values for μk between 0.007 and 0.521 for different foods were obtained. Peeling tests were performed by lifting sheets vertically away from a fresh mica surface. The adhes...

Research paper thumbnail of Nutritional Enhancement of Asian Wheat Products by Starch and Protein Supplementation

Food for Health in the Pacific Rim

... STONE, LA and LORENZ, K. 1984. The starch of Amaranthus - physico-chemical properties and fun... more ... STONE, LA and LORENZ, K. 1984. The starch of Amaranthus - physico-chemical properties and functional characteristics. StarchlStiirke 36, 232-237. ... Starch properties of the sweet potato, diploid Ipomeu frzmu (HBK) Don and tetraploid hybrids. StarchlStarke 43, 133-138. ...

Research paper thumbnail of Rice and Starch-Based Noodles

Science, Technology, and Processing, 2010

Research paper thumbnail of Physical properties and utilization of sweet potato starch and flour

published_or_final_versionBotanyDoctoralDoctor of Philosoph

Research paper thumbnail of Functional, digestibility, and antioxidant properties of brown and polished rice flour from traditional and new-improved varieties grown in Sri Lanka

Starch - Stärke, 2011

Sri Lankan traditional and improved rice varieties were processed into brown and polished rice fl... more Sri Lankan traditional and improved rice varieties were processed into brown and polished rice flours. Samples were analyzed for AM, protein, lipid, total phenolic content, and antioxidant activity. Gelatinization and retrogradation properties were observed in the Rapid Visco Analyzer (RVA) and DSC. The AM content of the samples was high to intermediate (20 to 26%) except for one which was low (17%). Brown rice flour (BRF) samples had lower swelling power, lower RVA viscoamylograph profile, lower gel hardness, lower gelatinization enthalpy but higher gelatinization peak temperature and lower melting enthalpies of its retrograded AP relative to its corresponding polished rice flour (PRF) samples. The BRF showed a lower decrease in peak viscosity in the RVA viscoamylograph as compared to its PRF when treated with a-amylase indicating inhibition potential. The traditional rice varieties had 68 to 86% higher total phenolic content (TPC) and 86 to 90% antioxidant activity in the BRF samples as compared to the improved varieties. A study on the antioxidant profile of the brown rice of the traditional rice varieties is being undertaken to explore their value as functional foods.

Research paper thumbnail of Effect of parboiling on the formation of resistant starch, digestibility and functional properties of rice flour from different varieties grown in Sri Lanka

Journal of the Science of Food and Agriculture, 2013

BACKGROUND: Hydrothermal treatment used in parboiling could induce formation of novel starch prop... more BACKGROUND: Hydrothermal treatment used in parboiling could induce formation of novel starch properties having potential food applications. In the current work, functional, digestible and retrogradation properties of flour from non-parboiled and steamed parboiled six rice varieties with high amylose content of around 30% but differing in length and width ratio were investigated and compared. RESULTS: The parboiling process reduced swelling volume and amylose leaching in all tested varieties. Among the varieties studied, the resistant starch content ranged from 1.6% in AT 306 to 0.46% in BG 357. Parboiling reduced the resistant starch content in AT 306 by about 50%, but it did not significantly affect the resistant starch content of the other varieties. The amylose-lipid complex remained unchanged after parboiling. Amylopectin retrogradation was not observed in parboiled rice. Amylose retrogradation was not seen except for AT 306. Pasting behaviour of parboiled rice flours showed high pasting stability and low setback. Flours were more susceptible to enzymatic hydrolysis after parboiling. Partial gelatinisation during parboiling was sufficient to produce grains with excellent milling quality showing a head rice recovery that ranged from 98% to 100% among the varieties studied. CONCLUSION: Degree of gelatinisation is the most important factor that determines the high head rice recovery. High pasting stability and low setback of flour of parboiled rice indicate some potential food applications.

Research paper thumbnail of Bihon-Type Noodles from Heat-Moisture-Treated Sweet Potato Starch

Journal of Food Science, 2001

Sweet potato starch (SPS) has limited uses in the Philippines, but modification of its properties... more Sweet potato starch (SPS) has limited uses in the Philippines, but modification of its properties may make it more suitable for use in traditional products that normally use other types of starch. Heat-moisture treatment was applied to native SPS (HMTSPS), which was used as a substrate and composite with maize starch (MS) to produce bihon-type starch noodles. Preliminary quality scoring showed that acceptability scores of raw starch noodles, plain boiled, and sautéed noodles made from 100% HMTSPS and 50% HMTSPS:50% MS were not significantly different from the commercial bihon. However, consumer testing is recommended to further validate acceptability of the sweet potato for bihon.

Research paper thumbnail of Genetic Variation in the Physical Properties of Sweet Potato Starch

Journal of Agricultural and Food Chemistry, 1999

Sweet potato starch, prepared from 44 genotypes adapted to Philippine conditions, showed wide var... more Sweet potato starch, prepared from 44 genotypes adapted to Philippine conditions, showed wide variation and distinctly different pasting profiles in Rapid Visco-Analyzer (RVA) analysis at 11% and 7% starch concentration. At 11% starch concentration, the pasting profiles were type A, characterized by high to moderate peak with a major breakdown and low cold paste viscosity. At 7%, the pasting profile was generally type C, characterized by the absence of a distinct peak with none to very slight breakdown and high cold paste viscosity. However, differentiation among genotypes was better achieved from RVA pasting profiles at 11% starch concentration. Peak viscosity (PV) and hot paste viscosity (HPV) at 11% starch paste concentration had significant negative correlation with amylose content. PV, HPV, and setback ratio were significantly correlated to adhesiveness of the starch gel. Sweet potato starch generally had high swelling volume but low solubilities at 92.5°C.

Research paper thumbnail of Accurate Estimation of Sweetpotato Amylase Activity by Flour Viscosity Analysis

Journal of Agricultural and Food Chemistry, 1999

Sweetpotato flour (SPF), prepared from 44 genotypes adapted to Philippine conditions, showed wide... more Sweetpotato flour (SPF), prepared from 44 genotypes adapted to Philippine conditions, showed wide variation in Rapid Visco-Analyzer (RVA) pasting characteristics due to its variation in composition and endogenous amylase activity. The RVA pasting parameters of peak viscosity determined in water (PV1) and that determined in 0.05 mM AgNO 3 (used as an amylase inhibitor) (PV2) were successfully used to estimate R-amylase activity. The correlation of the ratio (PV2-PV1)/PV1 to R-amylase activity was 0.96 (p < 0.01, N) 44). Swelling volume measurements were not found to be suitable for prediction of R-amylase activity.

Research paper thumbnail of Heat-moisture treatment effects on sweetpotato starches differing in amylose content

Food Chemistry, 1999

Sweetpotato starch from two genotypes, Taiwan (15.2% amylose) and 93-006 (28.5% amylose), were ex... more Sweetpotato starch from two genotypes, Taiwan (15.2% amylose) and 93-006 (28.5% amylose), were exposed to heat-moisture treatment (HMT) of 25% moisture at 110 C for various exposure times at`as-is' (pH 6.5±6.7) and alkaline pH (pH 10) conditions. In both starch samples at`as-is' pH, there was a shift from a Type A pasting pro®le (characterized by a high to moderate pasting peak, major breakdown after holding time at 95 C and low cold paste viscosity) to a Type C pasting pro®le (characterized by lack of a pasting peak and no breakdown, with high cold paste viscosity in 93-006; and a slight breakdown in Taiwan). With HMT at pH 10, the pasting peak viscosity was increased and low hot paste viscosities and high cold paste viscosities were observed. Under both pH conditions after HMT, there were marked increases in gelatinization temperatures and broadening of the DSC gelatinization endotherms, and considerable decreases in swelling volume and solubilities. Gel textures of HMT starch samples appeared to be related to amylose content. Taiwan starch gel had a marked increase in hardness and adhesiveness, while that of 93-006 did not show signi®cant dierences in hardness after HMT. Both starch samples showed a marked reduction in resilience, indicating a shift from a long stringy nature to short paste consistency. Starch gels exposed to HMT under alkaline conditions showed a high degree of syneresis.

Research paper thumbnail of Genetic Variation in Color of Sweetpotato Flour Related to Its Use in Wheat-Based Composite Flour Products

Cereal Chemistry, 1997

Cereal Chem. 74(5):681-686 Sweetpotato flours vary widely in color depending on genotype, and whe... more Cereal Chem. 74(5):681-686 Sweetpotato flours vary widely in color depending on genotype, and when used in wheat-based composite flours, they will impart characteristic colors which may be favorable or unfavorable for particular food products. Sweetpotato flour (SPF) was prepared from 44 genotypes and analyzed for proximate composition and biochemical properties. The Hunter Color L*, a*, b* values of the dry SPF and their modified Pekar slicks (PS) with water and with alkali were measured. Polyphenol oxidase activity, α-amylase activity, and total sugar were significantly correlated to L* values of dry SPF and of their PS tests with water and with alkali. The yellow pigment level was significantly correlated to the yellowness (b*) of the dry flour and of the PS test with water, but less correlated to b* of the PS test with alkaline. The results indicated a complex biochemical basis to SPF color, and no single biochemical factor examined was adequate to predict the color of a food product made from SPF. However, the PS color parameters were highly correlated with the color of dough sheets for white-salted and yellow-alkaline noodles made from wheat and sweetpotato composite flour (75:25). Thus, the simple modified PS test could be used in screening of genotypes for color stability and suitability for a specific end-use. SPF genotypes conferred a wide range of colors on composite flour dough preparations. Some colors, particularly the range of greens and bright orange, may be useful in specialty product development.

Research paper thumbnail of Production of Bihon-type Noodles from Maize Starch Differing in Amylose Content

Cereal Chemistry Journal, 2004

Cereal Chem. 81(4):475-480 Maize starches extracted from selected maize cultivars with 0.2-60.8% ... more Cereal Chem. 81(4):475-480 Maize starches extracted from selected maize cultivars with 0.2-60.8% amylose contents were used to produce bihon-type noodles. Starch dough using a pregelatinized starch binder was prepared and extruded through a laboratory-scale extruder simulating the traditional process of making bihon in the Philippines. The normal maize starches with amylose content of ≈28% were successfully used for bihon-type noodle production, but waxy maize starches with 0.2-3.8% amylose content and high-amylose maize starches with 40.0-60.8% amylose content failed to produce bihontype noodles. Viscoamylograph profile parameters and swelling volume are significantly correlated to amylose content of maize starch samples evaluated. These physicochemical properties may be used to indicate that the starch samples at normal amylose levels may be used for bihon-type noodles. Starch noodles produced in the laboratory were not significantly different in terms of either cooking quality or textural properties from two commercially produced maize noodle samples, except for adhesiveness. The laboratory process and fabricated extruder can be used to produce bihon-type noodles.