Effect of heat-moisture treatment on multi-scale structures and physicochemical properties of breadfruit starch

Combination treatment of bamboo shoot dietary fiber and dynamic high-pressure microfluidization on rice starch: Influence on physicochemical, structural, and in vitro digestion properties

The physicochemical, structural properties and digestibility of rice starch treated by bamboo shoot dietary fiber (BSDF) combined with dynamic high-pressure microfluidization (DHPM) were investigated. Compared with starch modified by BSDF alone, the combination treatment decreased the pasting viscosity and viscoelasticity of starch. Furthermore, the pasting viscosity and viscoelasticity showed an increase from 50 to 100 MPa and then decreased after increasing the pressure to 150 and 200 MPa. The enthalpy of gelatinization and relative crystallinity of starch treated by BSDF and 100 MPa DHPM significantly increased by 17% and 63%, respectively. Scanning electron microscopy images demonstrated that flaky BSDF coated on starch granules to form a protective layer. As a result, the fractions of resistant starch increased and the starch hydrolysis extent and rate decreased under 100 MPa DHPM. This study highlights an innovative and promising strategy for improving the properties of starch and facilitating its utilization.

Influence of moisture and amylose on the physicochemical properties of rice starch during heat treatment

Moisture and amylose are important factors affecting the quality of heat-treated starches. The amylose content in heat-treated rice starch increased as moisture content (MC) increased from 8% to 30%, but decreased at MC of 70%. With the increase of MC, the paste transmittance, gelatinization temperature, and digestibility of starch increased, whereas the swelling power and enthalpy decreased. The long- and short-range molecular order and the digestive properties of starch with MC ≤ 30% changed moderately, but high MC (70%) gelatinized the starch and drastically changed the physicochemical properties. High amylose content in rice starch led to low long- and short-range molecular order, swelling power, and gelatinization temperature, but increased resistant starch. The results indicated that 30% of MC separates effects of heat treatment of starch, where low MC (≤30%) and high amylose lowers digestibility, which is beneficial for diabetics, while high MC (>30%) promotes solubility and transparency.

Insight into the biphasic transition of heat-moisture treated waxy maize starch through controlled gelatinization

Biphasic transition is an important behavior of starch caused by heat-moisture treatment (HMT). Starch may change from typical single endotherm to biphasic endotherm (G1, G2) by HMT which corresponded to two viscosity peaks (PV₁ and PV₂) in pasting analysis. During PV₁, remarkable disruption of birefringence occurred in the inner region of starch granules, accompanied by a decreased relative crystallinity from 20.59 to 14.73%. Native starch completely lost their birefringence at 73 °C, while the HMT starch still showed strong birefringence in granule periphery. The HMT starch only lost crystallites at 80 °C (PV₂). A crystallite stability hypothesis was developed that G1 was mainly due to the gelatinization of the inner crystalline lamellae of starch granule, and the newly formed G2 was caused by the peripheral ones enhanced by HMT. This work also provided details on the mechanism of HMT and a potential method for the thermal transition study on starch.

Modification of Physicochemical Properties of Breadfruit Flour Using Different Twin-Screw Extrusion Conditions and Its Application in Soy Protein Gels

The objective was to modify functional properties of breadfruit flours using twin-screw extrusion and test the physicochemical properties of the extruded flours. Extruded breadfruit flours were produced with twin-screw extrusion using different last barrel temperature (80 °C or 120 °C) and feed moisture content (17% or 30%). These conditions resulted in four extruded flours with different mechanical (specific mechanical energy, SME) and thermal (melt temperature) energies. At temperatures below the gelatinization of the native starch (<70 °C), swelling power was increased in all extruded treatments. Solubility was dramatically increased in high-SME extruded flours at all tested temperatures. Water holding capacity was dramatically increased in the low-SME extruded flours. A two-fold higher cold peak viscosity was obtained for low SME-high temperature extruded flour compared with the other extruded flours. Low SME-low temperature extruded flour still exhibited a hot peak viscosity, which occurred earlier than in native flour. Setback was decreased in all extruded flours, especially in high-SME treatments. The incorporation of extruded flours into soy protein gels did not affect cooking loss, while hardness and springiness decreased with the addition of extruded flours. Overall, extrusion of breadfruit flour altered functional flour properties, including water holding capacity and pasting properties, and modified the texture of soy protein gels.

Carbohydrate and bioactive compounds composition of starchy tropical fruits and tubers, in relation to pre and postharvest conditions: A review

In some tropical countries, people are suffering from both undernourishment and noncommunicable disorders, such as overweight/obesity. Starchy tropical fruits and tubers are of particular interest for their carbohydrate content and for the micronutrients they provide. The present study summarizes the content in carbohydrate, phenolics, carotenoids, and vitamin C, as well as the antioxidant activity of a wide range of tropical fruits and tubers. The energy content of fruits and tubers studied is in the range of 1,200 to 1,800 kJ/100 g of dry weight. They are thus important staple foods and, due to their diversity and seasonality, they can provide energy all year long by alternating the resources in the human diet. Starchy fruit and tuber crops have antiobesity properties as they are bulky, rich in moisture, and contain less than 2% of fat. Noncolored fruit and tubers provide total phenolics at about 20 to 140 mEq/100 g fresh weight. They thus have a high antioxidant capacity, as related to their total phenolic content but also to the presence of carotenoids, such as lutein, mostly in Dioscorea bulbifera and cocoyam. Yellow and orange-fleshed varieties contain more total phenolics and also more provitamin A carotenoids than noncolored fleshed ones. The contents in total phenolic and carotenoid greatly vary with the species and variety. The influence of pre and postharvest conditions on micronutrient content is discussed. Further studies on new processing methods are needed to maximize polyphenols and carotenoids retention in the foods and increase the bioaccessibility of these compounds. PRACTICAL APPLICATION: This paper provides information on the nutritional quality of starchy tropical fruits and tubers. Nutritional quality is studied from the point of view of providing energy and bioactive compounds. The paper aims to promote the use of local resources in tropical areas, which could ultimately limit the adverse effects of food globalization on noncommunicable disorders. It could also lead to tropical countries being less dependent on food imports.

Effects of heat-moisture and acid treatments on the structural, physicochemical, and in vitro digestibility properties of lily starch

Starch extracted from lily bulb (Lilium brownii var. Viridulum Baker) was modified via heat-moisture treatment (HMT) at different moisture levels (15-35%) and acid treatment (AT) with hydrochloric acid at five different concentrations (0.25-2.0 M). The effects of HMT and AT on the physicochemical properties and in vitro digestibility of lily starch were investigated. HMT and AT led to the clustering of the starch granules, whose surface became rougher, thereby increasing the particle size. X-ray diffraction results showed that HMT increased the relative crystallinity and transformed the crystalline structure from B- to A-type. The relative crystallinity and X-ray patterns of the AT starch significantly increased. The swelling power of HMT and AT starch was significantly reduced, whereas the solubility of HMT starch decreased. The solubility of AT starch was significantly higher than that of native starch (NS) (p < 0.05). Differential scanning calorimetry revealed that the gelatinization temperature of lily starch was higher than that of NS after two modifications, whereas the gelatinization enthalpy of the NS was lower than that of the modified samples. The starch with HMT at 25% showed the highest resistant starch content of 44.15% in cooked samples.

The Compositional and Functional Attributes of Commercial Flours from Tropical Fruits (Breadfruit and Banana)

The objective of this study was to compare the compositional and functional properties of tropical flour sources (two breadfruit flours (type A and type B) and a banana flour) with a more traditional flour source (wheat flour). Macro-nutrient composition, pH, water and oil holding capacity, bulk density, particle size, solubility, swelling power, pasting properties, and thermodynamics (gelatinization and retrogradation) were determined. All flours evaluated were similar in their composition with high levels of carbohydrates (greater than 82.52 g/100 g on a dry-matter basis), with most of the carbohydrate content comprised of starch (greater than 67.02 g/100 g). The tropical fruit flours had greater (p < 0.05) water holding capacity than wheat flour. Breadfruit flour B had the lowest (p < 0.05) bulk density, while banana flour had the greatest (p < 0.05) bulk density. The swelling power of the tropical flours was greater (p < 0.05) than the wheat flour. The viscosity of the tropical flours was higher than wheat flour but decreased significantly when temperature was held at 130 °C. These results indicated that the two breadfruit flours and banana flour have great potential for application in processed food products, and have similar compositional attributes to a more traditional flour.

Cooking loss, texture properties, and color of comminuted beef prepared with breadfruit (Artocarpus altilis) flour

Cooking loss, texture properties, and color of comminuted beef when prepared with breadfruit (Artocarpus altilis) flour or other flour sources was evaluated using 2 separate studies. Flour sources tested in these studies (against a negative control with no added flour) were breadfruit flour, soy flour, corn flour, wheat flour, and tapioca flour. Study 1: Finely minced, comminuted beef batters (extra lean beef targeted to 97% lean and 3% fat, salt, and ice/water) prepared with inclusion levels of 0, 1, 2, 3, 4, and 5% flour were evaluated for cooking loss and texture. Cooking loss was reduced (P < 0.05) in comminuted beef prepared with breadfruit flour compared with those not prepared with flour and cooking loss decreased as breadfruit flour inclusion level increased (Linear P < 0.01). Hardness was not different (P = 0.49) in comminuted beef prepared with breadfruit flour compared with soy flour, and was much less (P < 0.01) compared with the 3 other flour sources at each inclusion level. Study 2: Comminuted beef (lean beef targeted to 90% lean and 10% fat, salt, and ice/water) with inclusion levels of 0, 2.5, and 5% flour were formed into patties and were evaluated for color over a simulated retail display period. Redness values (a*) of comminuted beef prepared with breadfruit flour were the greatest (P < 0.05) during the 7-d simulated retail display compared with all other treatments, including control samples with no flour. Overall, the results indicated that breadfruit flour could be effectively used as an ingredient in comminuted beef to produce similar texture as observed with soy flour, while actually improving redness values beyond that of other flour sources.

Evaluation studies on the combined effect of hydrothermal treatment and octenyl succinylation on the physic-chemical, structural and digestibility characteristics of sweet potato starch

In order to increase the degree of substitution (DS), a combination of heat-moisture treatment (HMT) and octenyl succinylation (OSA) was used to modify sweet potato starch (SPS). The content of OSA had significant influence on the DS of starch, and DS of HMT OSA-modified SPS (HOSA-SPS) was higher than that of OSA-modified SPS (OSA-SPS), indicating that prior HMT could enhance the reaction. HOSA-SPS showed higher contents of SDS and RS in comparison with OSA-SPS as OSA concentration was beyond 6%. HMT decreased swelling power of starch while OSA modification had a contrary role (p < 0.05). Scanning electron microscopy (SEM) showed starch was destroyed by OSA modification while HMT had slight effect on the structure. X-ray diffraction (XRD) indicated that crystal type of starch was transformed from C- to A-type resulted from HMT, and remained unchanged by OSA modification. The onset, peak, and conclusion gelatinization temperatures of starch increased by HMT and decreased by OSA modification (p < 0.05).