Pasting and Dough Rheological Properties of Ackee (Blighia sapida) Aril Flour: A Contribution to the Search for Wheat Flour Substitutes

Wheat is one of the most widely used cereals in the world. However, studies consider wheat flour doughs to be of low nutritional quality, as there is now greater public awareness of celiac disease and gluten intolerance. Therefore, consumers are demanding healthier and more varied food products. Consequently, wheat flour is being replaced fully or partially by flours from other sources with higher quality. Hence, the main objective of this work was to report the effect of blending wheat flour with ackee aril flour, until the total replacement of wheat flour, on pasting and dough rheological properties. Five different levels of blending were analyzed: wheat to ackee aril flour mass ratios of 100 : 0, 75 : 25, 50 : 50, 25 : 75, and 0 : 100. Pasting properties (pasting temperature, peak viscosity, ease of cooking, swelling power, final viscosity at 50 °C, and thixotropy) were analyzed; and steady-state shear measurements were used to obtain consistency coefficients ( K ) and flow behavior indexes ( n ) after data was fitted to the Power Law and Herschel-Bulkley models. The gradual addition of the ackee aril flour fraction produced an increase in ash, fat, protein, and fiber content; while water and carbohydrate content showed the opposite behavior in the obtained composite flour. Consequently, the partial or full replacement of wheat flour changed the rheological properties of the produced doughs, as well as the quality of the final product. These changes were mostly related to the protein and carbohydrate content of the ackee aril flour fraction. In general, doughs showed a pseudoplastic behavior with thixotropy whose viscosity decreased as the addition of ackee aril flour was increased. Pasting properties of blends involving 25 %-75 % ackee aril flour demonstrate the feasibility of including these flours in products subjected to high processing temperatures such as canned products or even to produce chips and pasta.

Biocomposites Based on Plasticized Wheat Flours: Effect of Bran Content on Thermomechanical Behavior

In the present work, the effect of different bran content on the overall thermomechanical behavior of plasticized wheat flours (thermoplastic wheat flour; TPWF) was investigated. Refined flour (F0) with negligible bran fiber content, F1 flour (whole grain flour, 20% wt. bran), F3 (50% wt. bran) and F2 (F1:F3, 50:50) film samples were realized by extrusion process. The effect of TPWF blending with two different biopolymers (polycaprolactone and poly butyrate adipate terephthalate), combined with the presence of citric acid as compatibilizer was also considered. Results from FESEM analysis and tensile characterization demonstrated that PCL was able to reach improved compatibility with the plasticized flour fraction at intermediate bran content (F2 based formulation) when 25% wt. of biopolymeric phase was added. Additionally, it was proved that improvements can be achieved in both thermal and mechanical performance when higher shear rate (120 rpm) and low temperature profiles (Tset2 = 130–135–140 °C) are selected. Disintegrability of the TPWF basic formulations in compositing conditions within 21 days was also confirmed; at the same time, an absence of any phytotoxic event of compost itself was registered. The obtained results confirmed the suitability of these materials, realized by adding different bran contents, to mechanically compete with bioplastics obtained by using purified starches.

The influence of milling and sifting processes on deoxynivalenol distribution in whole-wheat flour and its products

Milling and sifting of grain are important processes that affect mycotoxin distribution in the chain of grain products. The level of deoxynivalenol (DON) in white flour cannot be reduced by sifting because it is concentrated within a specific white flour fraction. The objective of this study was to investigate the influence of milling and sifting processes on the reduction of DON contamination in whole-wheat flour and in the chain of spring wheat products (grain – bran – white flour – white flour fractions) from artificially and naturally (2016) and naturally (2017) infected grain samples. The current study showed that the distribution of DON in the grain products (whole-wheat flour – bran – white flour) depends on the weather conditions of the season and grain contamination level. This was particularly evident in the naturally contaminated grain in 2017. The highest DON concentrations were determined in bran. Higher DON concentrations in the bran from the naturally infected grain indicate the protective function of the grain hull, which provides partial protection for grain embryo against higher contamination. With a delay in harvesting, which resulted in increased DON concentrations, bran remained the most contaminated product; however, this was not true for the products from artificially infected grain. The DON level in bran was not significantly different at P<0.05 from that in whole-wheat flour from artificially infected grain, it indicates that after inoculation, bran had biochemical compounds capable of significantly diminishing trichothecene production. It was investigated that DON levels were concentrated in white flour fractions 160 and 112 μm from naturally infected grains and in white flour fraction (residues) from artificially and naturally infected grains harvested later. The results obtained in this study could be further used for developing novel strategies aimed at limiting mycotoxin contamination in food and feed.