Process-Structure-Function in Association with the Main Bioactive of Black Rice Flour Sieving Fractions

Proximate Compositions, Texture, and Sensory Profiles of Gluten-Free Bario Rice Bread Supplemented with Potato Starch

Current gluten-free food development trends tend to favour pigmented rice flour. Bario Merah Sederhana is a type of red-pigmented rice that is indigenous to Sarawak, Malaysia. This research investigates the nutritional, texture, and sensory properties of gluten-free rice bread produced from a composite of BMS rice flour and potato starch, producing samples referred to as F1 (100:0), F2 (90:10), F3 (80:20), and F4 (70:30). The gluten-free rice bread formulations demonstrated higher ash and crude fibre content and lower carbohydrate content than wheat bread. However, the crude protein content of the bread decreased significantly (p < 0.05) with a decreased amount of rice flour, owing to wheat flour containing greater protein. The crumb of rice bread appeared to be darker due to the red pigment of rice flour; in contrast, the crust was lighter than the control sample, possibly due to a lower Maillard reaction. Among rice bread formulations, F4 demonstrated the lowest hardness in dough and bread, as well as the highest stickiness and springiness in dough and bread, respectively. The wheat bread received the highest rating (p < 0.05) in the sensory test; nonetheless, among the rice breads, F4 was considered to be an acceptable formulation owing to its high score in colour (7.03), flavour (5.73), texture (6.03), and overall acceptability (6.18). BMS has potential in gluten-free rice breads; the formulation of 70% rice flour combined with 30% potato starch was indicated to be acceptable.

Stability Kinetics of Anthocyanins of Grumixama Berries (Eugenia brasiliensis Lam.) during Thermal and Light Treatments

Grumixama (Eugenia brasiliensis Lam.) are red-colored fruits due to the presence of anthocyanins. In this paper, anthocyanin-rich extracts from grumixama were submitted to different temperatures and light irradiations, with the aim of investigating their stabilities. The thermal stability data indicated that a temperature range from 60 to 80 °C was critical to the stability of the anthocyanins of the grumixama extracts, with a temperature quotient value (Q₁₀) of 2.8 and activation energy (E_a) of 52.7 kJ/mol. The anthocyanin-rich extracts of grumixama fruits showed the highest stability during exposure to incandescent irradiation (50 W), followed by fluorescent radiation (10 W). The t_1/2 and k were 59.6 h and 0.012 h^-1 for incandescent light, and 45.6 h and 0.015 h^-1 for fluorescent light. In turn, UV irradiation (25 W) quickly degraded the anthocyanins (t_1/2 = 0.18 h and k = 3.74 h^-1). Therefore, grumixama fruits, and their derived products, should be handled carefully to avoid high temperature (>50 °C) and UV light exposure in order to protect the anthocyanins from degradation. Furthermore, grumixama fruits showed high contents of anthocyanins that can be explored as natural dyes; for example, by food, pharmaceutical and cosmetic industries. In addition, the results of this study may contribute to the setting of processing conditions and storage conditions for grumixama-derived fruit products.

PROFIL GELATINISASI DAN KOMPONEN ANTIOKSIDAN TEPUNG KETAN HITAM TERMODIFIKASI DENGAN ANNEALING

This research aims to study and characterize the effect of the annealing conditions (temperature and heating duration) on the gelatinization profile and antioxidant components of annealing-modified black glutinous rice flour (ABGRF). This experiment used a 2x3 factorial design consisted of temperature factor (54 and 58°C) and heating duration factor (4, 5, and 6 hours) with 2 replications. Research results showed that both factors and their interactions significantly affected all parameters of the gelatinization profile and antioxidant component of ABGRF (except through viscosity). Compared to its native, ABGRF showed an increase in peak viscosity, through viscosity (except treatment 54°C:5 hours), peak time and pasting tem-perature, indicated ABGRF resistance improvement to the heating process. Generally, the temperature treatment increment increased breakdown, setback, and final viscosity, but the heating duration increment decreased those values. The variation of ABGRF gelatinization profiles increased the diversification potential of BGRF-based food products. Annealing caused an overall decrease in ABGRF antioxidant ability. ABGRF produced by 54°C:4 hours treatment had the highest amount of antioxidant components (total anthocyanins contents 103.78±2.24 mg C3GE/100 g, total phenolic compounds 241.65±1.98 mg GAE/100 g, DPPH 267.14± 3.23 mg AAE/100 g, FRAP 473.94±1.43 mg AAE/100 g), thus using it as ingredients in functional food is more recommended, especially as composite flour for bread and cake.

Thermal Degradation Kinetics of Anthocyanins Extracted from Purple Maize Flour Extract and the Effect of Heating on Selected Biological Functionality

The thermal degradation of the anthocyanins and antioxidant activity in purple maize extracts was determined between 80 and 180 °C. The anthocyanins were found to be thermostable in the temperature range of 80 to 120 °C, whereas at higher temperatures the thermal degradation of both anthocyanins and antioxidant activity followed a first-order kinetic model. The z-values started from 61.72 ± 2.28 °C for anthocyanins and 75.75 ± 2.87 °C for antioxidant activity. The conformational space of pairs of model anthocyanin molecules at 25 and 180 °C was explored through a molecular dynamics test, and results indicated the occurrence of intermolecular self-association reactions and intramolecular co-pigmentation events, which might help explaining the findings of the degradation kinetics. The relationship between thermal degradation of anthocyanins and antioxidant activity and the in vitro release was further studied. The unheated extracts showed a high stability under gastric environment, whereas after heating at 180 °C, the digestion ended quickly after 60 min. After simulated intestinal digestion, the anthocyanins were slowly decreased to a maximum of 12% for the unheated extracts, whereas an 83% decrease was found after preliminary heating at 180 °C. The thermal degradation of anthocyanins was positively correlated with the in vitro decrease of antioxidant activity.