Perspectives on the history of research on starch Part V: On the conceptualization of amylopectin structure

Effects of yam varieties on flour physicochemical characteristics and resultant instant fufu pasting and sensory attributes

Challenges and constraints deter the effective gathering of adequate information specific to the characteristics of yam (Dioscorea rotundata) landraces capable of producing a promising instant pounded fufu product. This current work, therefore, investigated the effects of yam varieties on flour physicochemical characteristics and resultant instant fufu pasting and sensory attributes. The D. rotundata varieties, obtained from the International Institute of Tropical Agriculture (IITA) (yam-breeding programme) experimental plots, included commercially available Fekatsa (control), alongside ten (N = 10) improved (varieties) namely: TDr 08/00068, TDr 10/00912, TDr 89/02665, TDr 95/01932, TDr 95/18544, TDr 97/00632, TDr 97/00917, TDr Agwekachi, TDr Ebute, and TDr Meccakusa). Compared to control, the improved yam varieties produced promising characteristic range values, for instance, amylose (15.77-33.89%), bulk density (0.77-0.86 g/cm³), setback (99.5-503.46 RVU), peak time (4.93-7.00 min) along with peak temperature (83.99 °C). From the correlation coefficient and principal component analysis, it was possible to deduce how flour physicochemical characteristics were associated with the resultant instant fufu pasting and sensory attributes. Considering the totality of results of this current study, both TDr 10/00912, and TDr Meccakusa yam varieties demonstrate a high potential on instant pounded flour towards producing an acceptable quality and promising fufu product.

Starch structure and nutritional functionality - Past revelations and future prospects

Starch exists naturally as insoluble semi-crystalline granules assembled by amylose and amylopectin. Acknowledging the pioneers, we have reviewed the major accomplishments in the area of starch structure from the early 18th century and further established the relation of starch structure to nutritional functionality. Although a huge array of work is reported in the area, the review identified that some features of starch are still not fully understood and needs further elucidation. With the rise of diet-related diseases, it has never been more important to understand starch structure and use that knowledge to improve the nutritional value of the world's principal energy source.

Effect of pepsin and SO2 treatments on yield and properties of starch from Tabat and Wad-baco sorghum cultivars

This study aims to evaluate the effect of pepsin and SO₂ treatments on the yield and physicochemical-, functional-, and color properties of starches isolated from Tabat and Wad-baco sorghum cultivars. Results revealed that starch yield from treatments B (steeping for 7 h; 3 h in distilled water, 4 h in 0.1 M sodium acetate buffer, pH 4.5), BE (steeping for 7 h; 3 h in distilled water, 4 h in 0.1 M sodium acetate buffer, pH (4-4.5) with 250 mg pepsin), BES (steeping for 7 h; 3 h in distilled water, 4 h in 0.1 M sodium acetate buffer, pH 4.5 with 250 mg pepsin and 0.2% SO₂), and S (steeping for 7 h; 3 h in distilled water, 4 h in 0.2% SO₂) were significantly higher than that from the control (A; steeping for 24 h in 0.2% SO₂) in both cultivars. The combination of pepsin and SO₂ treatment (BES) produced an increased starch yield of 78.90% and 85.56% from Tabat and Wad-baco, respectively. Micrographs showed hydrolysis of the protein matrix attached to the starch by pepsin, which created holes on the surface of starch granule. Gelatinization temperature decreased in the treated starches from both cultivars compared to control. Water- and fat- absorption capacities were higher in the starch from all treatments compared to control. Generally, enzyme treatment improved the yield and functional properties of starches from both cultivars.

Impacts on performance of growing-finishing pigs under heat stress conditions: a meta-analysis

High ambient temperatures are a challenge for animal production around the world, and they are one of the major reasons for economic and productive losses in pig production. Under stress conditions, the energy contribution to productive functions is reduced, generating health imbalances, decreased productivity rates and changes in animal behavior. Despite the numerous articles published on this subject, the variability of results on performance parameters is high. For this reason, the objective of the present study was to evaluate the actual impact of high ambient temperature (HAT) (29 °C to 35 °C) on growing-finishing pig performance, compared with animals kept in a thermoneutral environment (TNT) (18 °C to 25 °C), based on meta-analysis. Data on average daily gain (ADG), average daily feed intake (FI) and feed gain ratio (F:G) were extracted from 22 (n = 22) papers published in scientific journals. The values were analyzed using an expansion of the t-test, considering the random effect of each study. Results showed that HAT reduced the values of ADG (654.38 vs 595.81 g/d) and FI (2.141 vs 1.875 g/d) when compared with the thermoneutral group. There was no statistical difference between the F:G values for both groups. In conclusion, high ambient temperatures negatively influence performance parameters of growing-finishing pigs when compared with those in thermoneutral conditions.

Understanding Starch Structure: Recent Progress

Starch is a major food supply for humanity. It is produced in seeds, rhizomes, roots and tubers in the form of semi-crystalline granules with unique properties for each plant. Though the size and morphology of the granules is specific for each plant species, their internal structures have remarkably similar architecture, consisting of growth rings, blocklets, and crystalline and amorphous lamellae. The basic components of starch granules are two polyglucans, namely amylose and amylopectin. The molecular structure of amylose is comparatively simple as it consists of glucose residues connected through α-(1,4)-linkages to long chains with a few α-(1,6)-branches. Amylopectin, which is the major component, has the same basic structure, but it has considerably shorter chains and a lot of α-(1,6)-branches. This results in a very complex, three-dimensional structure, the nature of which remains uncertain. Several models of the amylopectin structure have been suggested through the years, and in this review two models are described, namely the “cluster model” and the “building block backbone model”. The structure of the starch granules is discussed in light of both models.

From diets to foods: using linear programming to formulate a nutritious, minimum-cost porridge mix for children aged 1 to 2 years

BACKGROUND

Linear programming has been used extensively as a tool for nutritional recommendations. Extending the methodology to food formulation presents new challenges, since not all combinations of nutritious ingredients will produce an acceptable food. Furthermore, it would help in implementation and in ensuring the feasibility of the suggested recommendations.

OBJECTIVE

To extend the previously used linear programming methodology from diet optimization to food formulation using consistency constraints. In addition, to exemplify usability using the case of a porridge mix formulation for emergency situations in rural Mozambique.

METHODS

The linear programming method was extended with a consistency constraint based on previously published empirical studies on swelling of starch in soft porridges. The new method was exemplified using the formulation of a nutritious, minimum-cost porridge mix for children aged 1 to 2 years for use as a complete relief food, based primarily on local ingredients, in rural Mozambique.

RESULTS

A nutritious porridge fulfilling the consistency constraints was found; however, the minimum cost was unfeasible with local ingredients only. This illustrates the challenges in formulating nutritious yet economically feasible foods from local ingredients. The high cost was caused by the high cost of mineral-rich foods. A nutritious, low-cost porridge that fulfills the consistency constraints was obtained by including supplements of zinc and calcium salts as ingredients.

CONCLUSIONS

The optimizations were successful in fulfilling all constraints and provided a feasible porridge, showing that the extended constrained linear programming methodology provides a systematic tool for designing nutritious foods.

Localization and dynamics of amylose–lipophilic molecules inclusion complex formation in starch granules

Inclusion complex formation between lipophilic dye molecules and amylose polymers in starch granules is investigated using laser spectroscopy and microscopy.

The properties of different cultivars of Jinhai sweet potato starches in China

IR, (13)C NMR, X-ray diffraction and DSC applied to study the physicochemical properties of starches from six different cultivars of Jinhai (I-VI) sweet potato strains in China. Jinhai II showed the highest rate of retrogradation while Jinhai III showed the lowest in all studied cultivars. The hydrolysis rates of those starches by α-amylase were from 98.1% in Jinhai II to 99.9% in Jinhai VI with a mean value of 99.3%. The ratio of R (1158/991cm(-1)) in IR spectra of those six different sweet potato starches could be the feature to identify them. All of the six studied Jinhai sweet potato starches showed strong peak at diffraction angle (2θ) of 17°, 15° and 23°, meanwhile an extremely weak peak at 2θ around 5.5° was also identical. XRD pattern of Jinhai II and IV starch also gave strong diffraction peaks at 26.6°, which could be the characteristics of them. The enthalpy and Tp of Jinhai II were especially lower than other cultivars. Jinhai IV revealed two Tp of 128.0°C and 140°C, respectively. The second Tp was maybe the characteristic of Jinhai IV starch. IR and DSC were the most effective methods to distinguish different cultivars of sweet potato.

Properties of Edible Films Based on Oxidized Starch and Zein

The objective of this work was to investigate the effect of zein and film formulation on mechanical and structural properties of native (FNS), and oxidized with 2.5% (FOSA) and 3.5% (FOSB) banana starch. The oxidized starch showed differences from native starch due to the oxidation process, showing a decrease in lipids, proteins, and amylose. The increase of the sodium hypochlorite increased the content of carbonyl and carboxyl groups in the ranges 0.015–0.028% and 0.022–0.031%, respectively. The film obtained from FOSB displayed the highest tensile strength (5.05 MPa) and satisfactory elongation value (27.1%). The zein addition caused a decrease in these mechanical properties, as well as a significant decrease in water vapour permeability (WVP). However, films from FOSA and FOSB showed higher permeability than that of the native starch. The addition of glycerol and the level of oxidation increased the films moisture. Micrographs showed that, during the oxidation process, impurities were largely eliminated from the starch granule, noting more homogeneous structures both in granules and films.

The retrogradation properties of glutinous rice and buckwheat starches as observed with FT-IR, 13C NMR and DSC

The experiment was conducted to study the retrogradation properties of glutinous rice and buckwheat starch with wavelengths of maximum absorbance, FT-IR, (13)C NMR, and DSC. The results show that the starches in retrograded glutinous rice starch and glutinous rice amylopectin could not form double helix. The IR results show that protein inhabits in glutinous rice and maize starches in a different way and appearance of C-H symmetric stretching vibration at 2852 cm(-1) in starch might be appearance of protein. Retrogradation untied the protein in glutinous amylopectin. Enthalpies of sweet potato and maize granules are higher than those of their retrograded starches. The (13)C NMR results show that retrogradation of those two starches leads to presence of β-anomers and retrogradation might decompose lipids in glutinous rice amylopectin into small molecules. Glutinous rice starch was more inclined to retrogradation than buckwheat starch. The DSC results show that the second peak temperatures for retrograded glutinous rice and buckwheat starches should be assigned to protein. The SEM results show that an obvious layer structure exists in retrograded glutinous rice amylopectin.