Celiac disease is an immune-mediated disease caused by ingestion of gluten-containing products. The main aim of this study was to develop novel gluten-free doughnuts with high nutritional value using inulin and lupin flour. Five different doughnuts were formulated. Lupin flour was used to replace the potato starch–corn flour composite at levels of 15, 30, 45, 60 and 75% in gluten-free doughnut formulations (AF), (BF), (CF), (DF) and (EF), respectively. Inulin was added to all blends at a level of 6%. Doughnuts made with 100% wheat flour (C1) and 100% corn flour–potato starch blend (C2) served as the controls. The results indicated that the moisture, ash, fat, protein and crude fibre contents of the doughnuts were increased significantly (p < 0.05) with increasing levels of lupin flour. The rheological properties showed that the dough development time increased significantly (p < 0.05) with increasing lupin flour in the formulation with higher water absorption. The consumer acceptability sensory results varied among the different treatments. However, the AF, CF, and EF doughnuts had the highest value for flavour, texture and crust colour, respectively. Different levels of lupin flour can be used in gluten-free doughnuts production to improve their quality and to enhance their nutritional value in the presence of inulin at a 6% level. These results may have significant implications for the development of novel, healthier food products for gluten-sensitive consumers.

Celiac disease (CD) is an immunological mediated disorder that occurs to genetically susceptible individuals who suffer from gluten consumption. Therefore, the most effective treatment of CD is a life-long gluten-free diet. This study aimed to produce a nutritious gluten-free cinnamon roll, where resistant starch and lupine flour were used instead of wheat flour, in addition to 10% flaxseed flour and a fixed amount of hydrocolloid (1% xanthan gum). Eight different gluten-free cinnamon roll treatments (T1–T8) were produced with different ratios of resistant starch and lupine flour according to the following percentages (85:5, 80:10, 75:15, 70:20, 65:25, 60:30, 55:35 and 50:40, respectively). The proximate analysis, physical properties, color measurements and sensory evaluation of all cinnamon roll treatments and flours were determined. It was found that lupine and flaxseed flours in all different treatments had significantly (p ≤ 0.05) higher levels of ash, protein, lipid and crude fiber compared to wheat flour treatment (control treatment). However, carbohydrate levels were significantly (p ≤ 0.05) higher in control treatment compared with treatments 3–8. Gluten-free cinnamon rolls had significantly (p ≤ 0.05) higher levels of unsaturated fatty acids (oleic acid, linoleic acid and linolenic acid) than control. Further, there were significant differences in lightness (L*), redness (a*) and yellowness (b*) color values between the gluten-free and control treatments. The control cinnamon roll significantly (p ≤ 0.05) had the highest level of lightness and the lowest level of redness. The sensory evaluation obtained by consumer evaluation indicated that control cinnamon rolls significantly (p ≤ 0.05) received the highest score in overall impression, overall flavor, hardness and aftertaste. However, treatment 5 significantly (p ≤ 0.05) received the highest score in all the sensory scores in comparison with other gluten-free treatments. It is possible to develop a quality gluten-free cinnamon roll with respect to nutritional value manifested in higher levels of protein, fibers, unsaturated acids and prebiotics with acceptable sensory attributes.

Citrus fruits are widely consumed worldwide due to their nutritional and health benefits. However, the disposal of citrus waste poses significant environmental challenges. Orange peels (OP) are a substantial by-product of fruit processing and hold great potential as a source for bioethanol production, promoting investment in utilizing agricultural waste for biofuel purposes. OP offers a cost-effective substrate for producing value-added compounds, including bioethanol. Autoclaved-water treated OP biomass exhibited the highest release of reducing sugars (68.2%) this results supported by SEM images of that Autoclaving has definite effect on the structure of the OP particles. Among the five tested microbes, Candida tropicalis was selected as a promising bioethanol candidate due to its ethanol tolerance and ability to utilize xylose. Preliminary screening using Plackett-Burman Design (PBD) was conducted to identify six influential factors affecting the fermentation process at three levels, determining the optimum response region for bioethanol production by C. tropicalis. The significant variables were further investigated using Response Surface Methodology-Central Composite Rotatable Design (RSM-CCRD) at five levels, a novel approach in this study. The addition of cysteine and resazurin as reducing agents increased bioethanol production by 2.9 and 2.1 times, respectively, from the treated OP. Under the optimized conditions obtained from RSM-CCRD, bioethanol production reached 16.7 mg/mL per mg/ml reducing sugars. Implementing all the optimized conditions, including an initial pH of 5.75, 3% yeast extract, 2.25 g/L cysteine, 4% inoculum size, 0.6 g/L ZnSO4, 0.29 g/L MgSO4, 0.3 g/L MnSO4, and substrate treatment with active charcoal before fermentation, the bioethanol yield increased by 2.2 times after three days of fermentation using co-cultures of C. tropicalis and Kluyveromyces marxianus. The fermentation process was conducted at 30 °C and 150 rpm. Exploring OP as a low-cost renewable substrate and employing efficient microorganisms open new avenues for bioethanol production.

The authors wish to make corrections to the order of the authors