Impact of variety type and particle size distribution on starch enzymatic hydrolysis and functional properties of tef flours

All rights reserved. Tef grain is becoming very attractive in the Western countries since it is a gluten-free grain with appreciated nutritional advantages. However there is little information of its functional properties and starch digestibility and how they are affected by variety type and particle size distribution. This work evaluates the effect of the grain variety and the mill used on tef flour physico-chemical and functional properties, mainly derived from starch behavior. In vitro starch digestibility of the flours by Englyst method was assessed. Two types of mills were used to obtain whole flours of different granulation. Rice and wheat flours were analyzed as references. Protein molecular weight distribution and flour structure by SEM were also analyzed to justify some of the differences found among the cereals studied. Tef cultivar and mill type exhibited important effect on granulation, bulking density and starch damage, affecting the processing performance of the flours and determining the hydration and pasting properties. The color was darker although one of the white varieties had a lightness near the reference flours. Different granulation of tef flour induced different in vitro starch digestibility. The disc attrition mill led to higher starch digestibility rate index and rapidly available glucose, probably as consequence of a higher damaged starch content. The results confirm the adequacy of tef flour as ingredient in the formulation of new cereal based foods and the importance of the variety and the mill on its functional properties.The research was supported by the Spanish Institutions Ministerio de Economía y Competitividad and the European Regional Development Fund (FEDER) (Projects AGL2012-35088 and AGL2011-22669), and Comunidad de Castilla y León (Project VA252A12-2). W. Abebe thanks the Agencia Española de Cooperación Internacional (AECID) grant and Ethiopian Institute of Agriculture for providing the tef cultivars flours.Peer Reviewe

El Tef: cultivo de interés en el desarrollo de alimentos: estudio de sus características y potencial industrial

Se han estudiado las características ingenieriles y técnico-funcionales de la harina de tef [Eragrostis tef (Zucc.)Trotter] de tres variedades (DZ-01-99, DZ-Cr-37 y DZ-Cr-387), así como sus potenciales aplicaciones alimentarias. La variedad y el tipo de molino afectaron notablemente a sus características. En general presentaron peores características de flujo y más sensibilidad a cambios de humedad que las harinas de trigo y arroz. La viscoelasticidad de los geles y las propiedades texturales sugieren que las harinas de tef serían ingredientes adecuados en formulaciones de alimentos tipo gel. La incorporación de tef en masas panarias de trigo redujo ambos módulos viscoelasticos y aumentó la capacitancia mecánica de las masas, condujo a panes tipo chapata de calidad adecuada, con mayor contenido mineral y menor velocidad de digestión del almidón. Los panes con DZ-01-99 mostraron mayor contenido en flavonoides y actividad anti-radical que el resto de variedades y que el pan control

Effect of tef [Eragrostis tef (Zucc.) Trotter] grain flour addition on viscoelastic properties and stickiness of wheat dough matrices and bread loaf volume

Currently, consumers’ preference toward baked goods with additional (functional and nutritional) value is increasing, leading food industries to look at natural nutrient-dense alternatives like tef grain. Impact of tef grain flour incorporation (three Ethiopian varieties: DZ-01-99, DZ-Cr-37 and DZ-Cr-387 at 10, 20, 30 and 40 % levels) on dough viscoelastic profiles and stickiness of wheat-based dough matrices were investigated. Oscillatory and creep–recovery tests together with dough stickiness were performed. Incorporation of tef flours affected the structure of the dough matrices visibly by reducing viscoelastic moduli, and the maximum stress doughs can tolerate before its structure is broken and increased dough instantaneous and retarded elastic compliances. Effect of dose was not always significant in the parameters measured. Tef grain flour incorporation up to 30 % level led to breads with higher loaf volume than the control associated with optimal consistency and higher deformability of doughs. Higher tef doses increased dough stickiness. This will affect dough handling and shaping/flattening to get continuous strands or thin sheets. On average, the DZ-Cr-37-supplemented doughs exhibited higher elastic and viscous moduli, lower compliances and higher steady-state viscosity and led to significantly lower loaf bread volumes. Hence, based on dough viscoelastic and stickiness properties, incorporation of DZ-01-99 and DZ-Cr-387 into wheat flour-based formulations could be more preferable.This research was supported by the Spanish Institutions Ministerio de Economía y Competitividad and the European Regional Development Fund (FEDER) (Projects AGL2012-35088 and AGL2011-22669) and Comunidad de Castilla y León (Project VA252A12-2). W. Abebe thanks the Agencia Española de Cooperación Internacional grant and Ethiopian Institute of Agricultural Research for providing the flours of the tef varieties. Marina Villanueva thanks the Junta de Castilla y León doctorate grant.Peer reviewe

Effect of mill type and mechanical kneading conditions on fermentation kinetics of tef dough during injera making and phytate to mineral molar ratio of injera

Producción CientíficaInjera is Ethiopian traditional fermented flatbread which is made mostly from tef flour. Tef grain is milled and the flour kneaded to have batter-like dough which will ferment before injera baking. The influence of mill type: hammer mill (HM), disc mill (DM) and blade mill (BM) and mechanical kneading speed-time combinations (K1, K5, and K9) on fermentation kinetics was investigated. Phytate to mineral molar ratio (Fe, Zn and Ca) of tef injera was also investigated as affected by mill type and different kneading conditions. In both milling and kneading levels, maltose was the highest sugar concentration initially, followed by glucose and fructose. As fermentation continued, a similar trend in maltose breakdown was seen among HM, DM, and BM. However, different patterns of glucose and fructose breakdown were seen on HM than DM and BM. Similarly, HM had a different pattern in increment of lactic acid concentration than DM and BM. Similar trend in maltose concentration was seen between K1, K5, and K9. Again glucose breakdown and the increment of lactic acid in K9 were different than that of K1 and K5. Phytate/mineral molar ratio of BM was significantly different (p<0.05) from HM and DM. There was also a significant difference (p<0.05) in phytate/mineral molar ratio between K1, K5, and K9. Decreased phytate/mineral molar ratio was seen with increasing of kneading speed (rpm) for a longer period of time. The effect of mill type and kneading speed and time combinations on fermentation kinetics and phytate/mineral molar ratio were significant.Ministerio de Economía y Competitividad - FEDER (AGL2015-63849-C2-2-R)Junta de Castilla y León - FEDER (Project VA072P17

Influence of milling type on tef injera quality

Producción CientíficaInjera is an Ethiopian flat bread that is mostly made from tef flour. Injera making on an industrial scale holds a significant economic and social interest but requires a thorough study of how the process variables affect the product quality. The aim of this work was to investigate the effects of mill type (hammer, disc, and blade) on injera sensory quality and starch digestibility. The application of software for the determination of injera quality descriptors and its comparison with visual human eye evaluation was also established. Injera made with disc mill flour had higher overall acceptability (6.6) than that obtained from hammer mill (4.2) and blade mill (4.1) flours. The injera made with blade mill flour obtained the lowest rapidly available glucose and rapidly digestible starch. The outcome of introducing software for the determinations of injera number of eyes was found effective; its difference with human eye determination was insignificant.Ministerio de Economía y Competitividad - FEDER (AGL2015-63849-C2-2-R)Junta de Castilla y León - FEDER (Project VA072P17

The effect of mechanical kneading and absit preparation difference on tef injera quality

Producción CientíficaThe aim of this study was to investigate the effect of mechanical kneading and ‘absit’ preparation difference on the quality of tef injera, the staple food of Ethiopians. Standard methods were adopted to determine the starch fraction, total phenol, flavonoid, phytate and tannins of injera. Sensory injera quality was assessed using 9-point-hedonic scale. Change in kneading conditions (time/speed) did not significantly affect the free sugar (FSG), slowly digestible starch (SDS), resistant starch (RS), total starch(TS) and starch digestion rate index (SDRI). On the other hand, significant variation was observed in rapidly available glucose and rapidly digestible starch (RAG and RDS). Flavonoids, total phenolics and phytate contents varied significantly at different kneading time- speed combinations. Injera sensory quality was also significantly affected due to change in kneading conditions. Kneading condition 5 (3 min at speed 6) has the highest injera overall acceptability while kneading condition 9 (7 min at speed 12) had the lowest. In addition to kneading conditions, absit preparation (water to fermented dough ratio) was also found to affect the quality of tef injera. Absit # 3 made from 100 ml of fermented dough and 900 ml of water had the highest injera overall acceptability while, the lowest was observed on Absit # 4 made from 300 ml of fermented dough and 100 ml of water. In conclusion, both kneading and absit preparation significantly influenced starch hydrolysis, flavonoids, total phenolics and phytate contents as well as sensory quality of injera.Ministerio de Economía y Competitividad - FEDER (AGL2015- 63849-C2-2-R)Junta de Castilla y León) - FEDER (Project VA072P17

Lipase inactivation kinetics of tef flour with microwave radiation and impact on the rheological properties of the gels made from treated flour

Producción CientíficaIn recent years, many efforts are being made to produce tef-based food for its nutritive and health-promoting advantages. Tef grain is always whole milled because of its tiny grain size and whole flours contain bran (pericarp, aleurone, and germ) where major non-starch lipids could be deposited along with the lipid-degrading enzymes: lipase and lipoxygenase. As lipoxygenase shows little activity in low moisture, the inactivation of lipase is the common objective for most heat treatments to extend the shelf life of flours. In this study, tef flour lipase inactivation kinetics via hydrothermal treatments assisted using microwaves (MW) were studied. The effects of tef flour moisture level (12%, 15%, 20%, and 25%) and MW treatment time (1, 2, 4, 6, and 8 min) on flour lipase activity (LA) and free fatty acid (FFA) content were evaluated. The effects of MW treatment on flour pasting characteristics and the rheological properties of gels prepared from the treated flours were also explored. The inactivation process followed a first-order kinetic response and the apparent rate constant of thermal inactivation increased exponentially with the moisture content of the flour (M) according to the equation 0.048·exp (0.073·M) (R2 = 0.97). The LA of the flours decreased up to 90% under the studied conditions. MW treatment also significantly reduced (up to 20%) the FFA level in the flours. The rheological study confirmed the presence of significant modifications induced by the treatment, as a lateral effect of the flour stabilization process.Ministerio de Ciencia e Innovación (PID2019-110809RB-I00/AEI/10.13039/501100011033)Junta de Castilla y León/FEDER VA195P2

Etiquette of the antibiotic decision-making process for surgical prophylaxis in Ethiopia: a triangulated ethnographic study

BackgroundProphylactic antibiotics reduce surgery-associated infections and healthcare costs. While quantitative methods have been widely used to evaluate antibiotic use practices in surgical wards, they fall short of fully capturing the intricacies of antibiotic decision-making in these settings. Qualitative methods can bridge this gap by delving into the often-overlooked healthcare customs that shape antibiotic prescribing practices.AimThis study aimed to explore the etiquette of the antibiotic decision-making process of surgical prophylaxis antibiotic use at Tikur Anbessa Specialized Hospital (TASH).MethodsThe observational study was carried out at TASH, a teaching and referral hospital in Addis Ababa, Ethiopia, from 26 August 2021 to 1 January 2022. Overall, 21 business ward rounds, 30 medical record reviews, and 11 face-to-face interviews were performed sequentially to triangulate and cross-validate the qualitative observation. The data were collected until saturation. The data were cleaned, coded, summarized, and analyzed using the thematic analysis approach.ResultSurgical antibiotic prophylaxis (SAP) discussions were infrequent during surgical ward rounds in TASH, leading to practices that deviated from established recommendations. Clear documentation differentiating SAP from other antibiotic uses was also lacking, which contributed to unjustified extended SAP use in the postoperative period. Missed SAP documentation was common for emergency surgeries, as well as initial dose timing and pre-operative metronidazole administration. Importantly, there was no standardized facility guideline or clinical protocol for SAP use. Furthermore, SAP prescriptions were often signed by junior residents and medical interns, and administration was typically handled by anesthesiologists/anesthetists at the operating theater and by nurses in the wards. This suggests a delegation of SAP decision-making from surgeons to senior residents, then to junior residents, and finally to medical interns. Moreover, there was no adequate representation from pharmacy, nursing, and other staff during ward rounds.ConclusionDeeply ingrained customs hinder evidence-based SAP decisions, leading to suboptimal practices and increased surgical site infection risks. Engaging SAP care services and implementing antimicrobial stewardship practices could optimize SAP usage and mitigate SSI risks

Suitability of tef varieties in mixed wheat flour bread matrices: A physico-chemical and nutritional approach

Wheat flour replacement from 0 to 40% by single tef flours from three Ethiopian varieties DZ-01-99 (brown grain tef), DZ-Cr-37 (white grain tef) and DZ-Cr-387 (Quncho, white grain tef) yielded a technologically viable ciabatta type composite bread with acceptable sensory properties and enhanced nutritional value, as compared to 100% refined wheat flour. Incorporation of tef flour from 30% to 40% imparted discreet negative effects in terms of decreased loaf volume and crumb resilience, and increase of crumb hardness in brown tef blended breads. Increment of crumb hardness on aging was in general much lower in tef blended breads compared to wheat bread counterparts, revealing slower firming kinetics, especially for brown tef blended breads. Blended breads with 40% white tef exhibited similar extent and variable rate of retrogradation kinetics along storage, while brown tef-blended breads retrograded slower but in higher extent than control wheat flour breads. Breads that contains 40% tef grain flour were found to contain five folds (DZ-01-99, DZ-Cr-387) to 10 folds (DZ-Cr-37) Fe, three folds Mn, twice Cu, Zn and Mg, and 1.5 times Ca, K, and P contents as compared to the contents found in 100% refined wheat grain flour breads. In addition, suitable dietary trends for lower rapidly digestible starch and starch digestion rate index were met from tef grain flour fortified breads.Authors gratefully acknowledge the financial support of the Spanish Institutions Ministerio de Economía y Competitividad (Projects AGL2011-22669 and AGL2012-35088) and Comunidad de Castilla y León (Project VA252A12-2).Peer Reviewe

In vivo Wound Healing Activity of 70% Ethanol Leaf Extract of Becium grandiflorum Lam. (Lamiaceae) in Mice

Becium grandiflorum Lam. (Lamiaceae)is used as a traditional medicine against malaria, “Mich” and for treatment of spider bite that culminates in wound. The present study evaluated the potential wound healing activity of the crude extract of B. grandiflorum using rodent wound models. Hydroalcoholic (70% ethanol) leaf extract of B. grandiflorum was formulated as 5% and 10% ointment and its activity was investigated in excision and incision wound models using simple ointment and nitrofurazone as a negative and positive control, respectively. In addition, histopathological analysis was performed. Parameters, including rate of wound contraction, period of complete epithelialization, and skin tensile strength were evaluated. Both 5% (w/w) and 10% (w/w) extract ointments (p &lt; 0.001) and standard drug nitrofurazone (p &lt; 0.001) significantly reduced wound area compared to the negative control. Similarly, both doses of the extract ointment preparations showed significant increase (p &lt; 0.001) in wound tensile strength in the incision wound model. However, it was only 5% of the extract ointment and the standard that significantly shortened epithelialization time (p &lt; 0.001) compared to controls. These findings collectively indicate that ointments prepared from 70% ethanol leaf extract of B. grandiflorum could facilitate the different phases of wound repair, providing support for the traditional claims of the plant in the treatment of wound.Keywords: wound healing, excision model, incision model, Becium grandiflorum, hydroalcoholic extrac