INTRODUCTIONThe growth in diet-related illnesses such as obesity,cardiovascular diseases, and some types of cancer ledthe World Health Organization (WHO) and other relatedorganizations to encourage the consumption of fortifiedfood [1]. Fortification is a deliberate addition of essentialnutrients to a product to conserve its nutritional quality,enhance its added value, provide it with some functions,as well as to prevent or correct a particular nutritionaldeficiency in the population [2, 3]. However, one of theessential requirements of fortification is an appropriatefood vehicle. Food vehicles should be widely consumedby a large proportion of the population to be able to meetthe nutritional needs of the target group [4].Baked food products are good potential vehiclesof micronutrients and bioactive compounds becausethey are consumed all over the world by children andadults. Muffin is one of the most common bakery41Ndinchout A.S. et al. Foods and Raw Materials, 2022, vol. 10, no. 1, pp. 27–39products appreciated by people due to its taste and softtexture. Muffins are ready-to-eat snack food, similarto cupcakes, which are usually eaten at breakfast, asevening snacks, for tea, or at other meals. Muffins arealso served as snacks during many celebrations. Aspecial feature of muffins is their porous structure thatleads to high volume and spongy texture [5, 6].In response to the increasing demand for healthy,natural, and functional products, scientists are doingtremendous work in collaboration with industries toimprove the nutritional quality of food products. Sincefruits and vegetables are rich in natural nutrients,phytochemicals, and phenolic compounds withbiological properties, incorporating them in muffinsis a good way to fulfill the desires of consumers [7].Furthermore, natural antioxidants from fruits andvegetables may inhibit lipid peroxidation in food andimprove food quality and safety [5].Dacryodes macrophylla L. is a fruit tree belonging tothe Buseraceae family that is widespread in Cameroon,Equatorial Guinea, and Gabon. The fruits are commonlyconsumed directly or used to make natural juices andjelly [8]. D. macrophylla L. has red color that indicatesthe presence of phenolic compounds (e.g., anthocyanin)and some minerals (e.g., iron).To the best of our knowledge, there are no availablepublished data on D. macrophylla L. fruits as a potentialvalue-added ingredient of muffins. Nevertheless,in our previous work, we studied the dyeability andbacterial resistance of these fruits on woolen fabric [9].Ngondi et al. also showed that hydroethanolic extractof D. macrophylla L. fruits could have anti-obesity andantioxidant properties [10].Therefore, we aimed to develop value-addedmuffins fortified with D. macrophylla L. fruits and tostudy the impact of that incorporation on the qualityand acceptability of muffins. To achieve this aim, wefortified muffins with 1% of D. macrophylla L. fruit.Then, we evaluated their physicochemical properties,rheological parameters, and sensory characteristics. Inaddition, we determined the antioxidant properties offortified muffins to assess their functionality.STUDY OBJECTS AND METHODSStudy objects. We studied two groups of muffins:with egg and without egg. Each group contained acontrol and experimental samples with 0.5 and 1% ofDacryodes macrophylla L. extract instead of wheatflour.Materials. Wheat flour (maida), sugar, bakingsoda, baking powder, egg, vegetal oil (soybean), andliquid milk (green packet Verka) were purchased froma local supermarket (Amritsar, India). 2,2-diphenyl-1-picrylhydrazyl (DPPH), 6-hydroxy-2,5,7,8-tetramethylchronan-2-carboxylic acid (Trolox), and ascorbicacid were obtained from Sigma-Aldrich CompanyLtd. (St Louis, MO, USA). Analytical grade methanol,NaOH, NaCl, HNO3, H2SO4, and HClO4 were providedby Sisco Research Laboratories Ltd. (Mumbai, India).We used such equipment as an orbital shaker (Remi,Mumbai, India), a rotary evaporator (IKA Werke GmbHand Co. KG, Staufen, Germany), and a freeze dryer(Christ Beta 2-8 LD plus, Germany). Freeze-driedD. macrophylla L. was used to enhance the antioxidantsand color of muffins.Preparation of D. macrophylla L. extract. Theseeds of fresh D. macrophylla L. fruit were discardedand the rest of the pulp was dried in a freeze dryer,followed by an extraction with 70% ethanol in an orbitalshaker for 2 h at 200 rpm. It was then centrifugedat 4000 g for 10 min at 25°C and the supernatantwas collected. The residue was re-extracted andthe supernatant was collected and concentrated in arotary evaporator under reduced pressure at 45°C. Theremaining water was eliminated in the freeze dryer andthe DME was kept in a fridge at –70°C in sealed plasticcontainers for the following experiments.Preparation of muffins. Sugar was first powderedwith a mixer and eggs were manually beaten in a bowlwith a spoon (just for mixing purposes) for 1 min beforeweighing. All the ingredients were then weighed toprepare six different muffins (Table 1). Preliminarybaking was done to standardize the formulationof muffins and to find the sensorily acceptableconcentration of D. macrophylla L. extract.Then, the required number of eggs was mixedwith sugar using an electric hand mixer until creamy.Sunflower oil was added to the creamy mixture, whichwas continuously mixing, followed by the requiredamount of liquid milk. After about 4 min of mixing,wheat flour was gradually added to the emulsifiedgel during continuous stirring in the same direction.Baking powder was the last ingredient to be added tothe formulation. The dough was then introduced intogreased muffin molds and baked in the preheated ovenat 210°C for 8 min. The muffins were allowed to standfor 2 min in the oven and then taken out to cool down forabout 30 min at room temperature.The samples were then kept in sealed plastic foodgradebags at room temperature for further analysis. Foreggless muffins, the first step was to mix sugar with oiland the last step was to add baking soda after bakingpowder. For fortified muffins, D. macrophylla L. extractwas dissolved in liquid milk before being added to themixture (with egg and without egg).Rheology of dough. Rheological tests of muffindough were performed with a rheometer (MCR-102,Anton Paar Austria) as reported by Jantider et al. [11].The dough sample was loaded between two parallelplate geometric probes of 40 mm in diameter (PP40) andkept for 5 min (for equilibration). The gap between theplates was 1 mm and the sample was run at 25°C. Stresswas set at 0.1 Pa and frequency at 1 rad/s according tothe linear viscoelastic region. The measurements ofstorage modulus (G’, solid component) and loss modulus(G’’, liquid component) were recorded.Specific gravity of dough. The specific gravityof each type of muffin dough was determinedgravimetrically by dividing the weight of a known42Ndinchout A.S. et al. Foods and Raw Materials, 2022, vol. 10, no. 1, pp. 27–39volume of dough by the weight of an equal volume ofwater. A standard container was used for measurements[12].Moisture content. The gravimetric method was usedto determine the moisture content in muffin crumb. Forthis, 2 g of a sample was dried in an air oven at 105°Cuntil no further weight change, using a clean, dry, andpre-weighed aluminum moisture dish. The moisturecontent was calculated as follows:Mg =1,645( ) 400.8 VsY XMoisture content (%) = 100 –(W1 – W2)W1× 100Weight loss (%) =(Wd – Wm)Wd× 100 Crude fat (%) =W2W1× 100Ash (%) =W2W1× 100 Calcium content =Volume of EDTA usedVolume of sample used× 100Mg =1,645( ) 400.8 VsY XMoisture content (%) = 100 –(W1 – W2)W1× 100Weight loss (%) =(Wd – Wm)Wd× 100 Crude fat (%) =W2W1× 100=W2W1× 100 Calcium content =Volume of EDTA usedVolume of sample used× 100Mg =1,645( ) 400.8 VsY XMoisture content (%) = 100 –(W1 – W2)W1× 100loss (%) =(Wd – Wm)Wd× 100 Crude fat (%) =W2W1× 100W2W1× 100 Calcium content =Volume of EDTA usedVolume of sample used× 100where W1 is the weight of samples before drying; W2 isthe weight of samples after drying (in grams).Weight loss. The baking loss of muffins wasdetermined in percentage based on the weight of muffinafter baking and the weight of muffin dough by using thefollowing formula [13]:Mg =1,645( ) 400.8 VsY XMoisture content (%) = 100 –(W1 – W2)W1× 100Weight loss (%) =(Wd – Wm)Wd× 100 Crude fat (%) =W2W1× 100Ash (%) =W2W1× 100 Calcium content =Volume of EDTA usedVolume of sample used× 100Mg =1,645( ) 400.8 VsY XMoisture content (%) = 100 –(W1 – W2)W1× 100Weight loss (%) =(Wd – Wm)Wd× 100 Crude fat (%) =W2W1× 100Ash (%) =W2W1× 100 Calcium content =Volume of EDTA usedVolume of sample used× 100Mg =1,645( ) 400.8 VsY XMoisture content (%) = 100 –(W1 – W2)W1× 100Weight loss (%) =(Wd – Wm)Wd× 100 Crude fat (%) =W2W1× 100Ash (%) =W2W1× 100 Calcium content =Volume of EDTA usedVolume of sample used× 100Where Wd is the weight of dough; Wm is the weight ofmuffin.Muffin height and diameter. A digital caliper wasused to measure the height of muffins (from the highestto the lowest point) and their diameters (mm).Water activity. The water activity of the sampleswas measured by placing about 2 g of muffin crumb ona plastic dish of a water activity meter (AquaLab TE,series 3B, version 3.4, Decagon). After calibration withwater, values were recorded at 25°C in triplicate.Muffin volume. The volume of muffins wasdetermined by the millet-seed displacement method asdescribed by Rashida et al., with slight modification [5].An empty baker was filled with millet seeds and then theseeds were transferred into a container. Then, a muffinwas placed in the center of an empty baker and the seedswere loaded back from the container. The remainingseeds were put in a measuring cylinder and their volume(in mL) represented the volume of the muffin. Thespecific volume was then calculated by dividing thevolume recorded by the weight of the muffin (mL/g).Crude fat. Crude fat of the muffins was estimatedgravimetrically on the Soxhlet apparatus [13]. Thesamples were weighed (W1) and lipid was extracted withhexane for 6 h at 65°C. The lipid extract was then driedin the oven at 102°C till constant weight. Crude fat wasexpressed in percentage and calculated as follows:Mg =1,645( ) 400.8 VsY XMoisture content (%) = 100 –(W1 – W2)W1× 100Weight loss (%) =(Wd – Wm)Wd× 100 Crude fat (%) =W2W1× 100Ash (%) =W2W1× 100 Calcium content =Volume of EDTA usedVolume of sample used× 100Mg =1,645( ) 400.8 VsY XMoisture content (%) = 100 –(W1 – W2)W1× 100Weight loss (%) =(Wd – Wm)Wd× 100 Crude fat (%) =W2W1× 100Ash (%) =W2W1× 100 Calcium content =Volume of EDTA usedVolume of sample used× 100Mg =1,645( ) 400.8 VsY XMoisture content (%) = 100 –(W1 – W2)W1× 100Weight loss (%) =(Wd – Wm)Wd× 100 Crude fat (%) =W2W1× 100Ash (%) =W2W1× 100 Calcium content =Volume of EDTA usedVolume of sample used× 100Where W1 is the weight of a sample in grams beforelipid extraction; W2 is the weight of the dried lipidextract.Ash content. Total ash was determined by theincineration method in a muffle furnace. The sampleswere weighed in porcelain crucibles and incinerated for1 h at 550 ± 10°C. White ash was cooled and weighed.Ash content was expressed in percentage by using thefollowing formula:Mg =(  VsY XMoisture content (%) = 100 –Weight loss (%) =(Wd – Wm)Wd× 100 Ash (%) =W2W1× 100 Calcium Mg =1,645( ) 400.8 VsY XMoisture content (%) = 100 –(W1 – W2)W1Weight loss (%) =(Wd – Wm)Wd× 100 Crude fat Ash (%) =W2W1× 100 Calcium content =Mg =1,645( ) 400.8 VsY XMoisture content (%) = 100 –(W1 – W2)W1Weight loss (%) =(Wd – Wm)Wd× 100 Crude fat (%) =Ash (%) =W2W1× 100 Calcium content =Volume Where W1 is the weight of a sample in grams beforeincineration; W2 is the weight of the sample afterincineration.Mineral content. Preparation of samples. Thedefatted muffins and extracts were digested using amixture of tri-acid [14]. Three milliliters (3 mL) of triacid(HNO3:H2SO4:HClO4 = 5:1:1) was added to 0.5 gof a sample and the mixture was heated at 80°C. Afterabout 2 min, two milliliters (2 mL) of tri-acid wasadded again under continuous heating until the fume ofthe mixture became transparent. The digested sampleswere then cooled at room temperature and the volumewas made up to 20 mL with double distilled water.After filtration with Whatman filter paper, the solutionwas diluted to 100 mL with double distilled water andstored at room temperature as a stock sample solution formineral estimation.Calcium. To quantify calcium content, 5 mL ofthe stock sample solution was diluted to 50 mL withdouble distilled water. 2 mL of NaOH 1N was added andthen a pinch (about 100 mg) of the murexide indicator(a mixture of grind 0.2 g of ammonium purpurate with100 g of NaCl) to turn the solution pink.The pink sample solution was then titrated withEDTA solution, 0.01 M (3.723 g of EDTA dissolved in1000 mL of water) until the pink color turned darkpurple. The endpoint of titration was determined bycomparing the endpoint color of the sample to the oneTable 1 Formulation of muffinsIngredients, g Eggless muffins Egg-containing muffinsControl 1% DME 0.5% DME Control 1% DME 0.5% DMEWheat flour 149 148.5 149.25 150 148.5 149.25Sugar 85 85 85 85 85 85Vegetal oil 75 75 75 75 75 75Milk 75 75 75 75 75 75Baking powder 5.1 5.1 5.1 5.1 5.1 5.1Eggs 0 0 0 75 75 75Baking soda 1 1 1 0 0 0D.M. extract 0 1.5 0.75 0 1.5 0.7543Ndinchout A.S. et al. Foods and Raw Materials, 2022, vol. 10, no. 1, pp. 27–39obtained with the blank (titration with 50 mL of water).The calcium content (mg/g) was calculated as follows:Mg =1,645( ) 400.8 VsY XMoisture content (%) = 100 –(W1 – W2)W1× 100Wd – Wm)Wd× 100 Crude fat (%) =W2W1× 100× 100 Calcium content =Volume of EDTA usedVolume of sample used× 100Mg =1,645( ) 400.8 VsY Xcontent (%) = 100 –(W1 – W2)W1× 100– Wm)Wd× 100 Crude fat (%) =W2W1× 100× 100 Calcium content =Volume of EDTA usedVolume of sample used× 100Mg =1,645( ) 400.8 VsY Xcontent (%) = 100 –(W1 – W2)W1× 100Wm)× 100 Crude fat (%) =W2W1× 100100 Calcium content =Volume of EDTA usedVolume of sample used× 100Magnesium. To determine the magnesium content,we first estimated the hardness (Ca + Mg) of thesamples. For this, 5 mL of the stock solution was dilutedto 50 mL with water in a conical flask, followed by theaddition of 1 mL of the buffer solution and about 100 mgof the EBT indicator (a mixture of grind 0.40 g ofErichrome with 100 g of NaCl). The wine red colordeveloped and the titration was done with 0.01 M ofEDTA. The endpoint was reached by comparing theblue color of the sample solution with the one obtainedwith the blank (water). Then, magnesium was measuredin mg/ml by subtracting the volume of EDTA used todetermine hardness to the one used to quantify calcium:Mg =1,645( ) 400.8 VsY XMoisture content (%) = 100 –(W1 – W2)W1× 100loss (%) =(Wd – Wm)Wd× 100 Crude fat (%) =W2W1× 100=W2W1× 100 Calcium content =Volume of EDTA usedVolume of sample used× 100Where Y is the volume of EDTA used to estimatehardness, mL; X is the volume of EDTA used to quantifycalcium, mL; and Vs is the volume of a sample, mL. Theresult was expressed in mg/g of the sample.Phosphate. The phosphate content was determinedspectrophotometrically at 625 nm. Five milliliters (5 mL)of the stock solution was diluted to 50 mL with waterand then mixed with 2 mL of ammonium molybdatereagent (prepared by mixing 25 g ammonium molybdatedissolved in 175 mL water and 280 mL H2SO4 dilutedwith 400 mL of water and making the final volume upto 1000 mLwith distilled water) and 0.5 Ml of stannouschloride (2.5 g SnCl2 dissolved in 100 mL water). Themixture was kept for 15 min and then used to recordoptical density against the blank on a microplate reader.Potassium, Sodium and Zinc. These elementswere analyzed by atomic absorption spectrometry [15].KCl, NaCl, and ZnSO4 were used as a standard toquantify K, Na, and Zn, respectively. A serial dilutionof each standard was performed to make a calibrationcurve for each element. Subsequently, the filtratedliquor from mineralization of each sample was dilutedwith double distilled water and the content of mineralswas determined at 766.5 nm for K, 330.2 nm for Na,and 213.9 nm for Zn with an AA 6300 spectrometer(Shimadzu, Tokyo, Japan) against the blank byextrapolation of absorbance on the calibration curve ofeach element. The final amount (dry weight) was thencalculated in mg/g of the sample.Muffin color. The color of the muffins wasdetermined the next day after preparation by recordingthe L*, a*, and b* values of crust and crumb. Aspectrophotometer with spectra match software wasused according to the CIE Lab color scales, where Lgoes in a range of 0 to 100 from dark to light, a* fromgreen to red, and b* from blue to yellow. Color valueswere measured three times at three different points oneach muffin and then averaged.Texture analysis. The texture profile of crumbcubes (12.5 mm3) from the middle of the muffins wasdetermined using a texture analyzer (Model EZ-SX,Stable microsystems, Shimadzu, UK) equippedwith a 5-kg load cell [16]. A double compression testwas performed by putting a crumb cube sample inthe center of a heavy-duty platform (HD P/90) andsubjecting it to compression (50%) with an aluminum75-mm cylindrical probe (P/75) at 1 mm/s. The textureparameters (firmness, cohesiveness, gumminess,chewiness, and springiness) were calculated based onthe texture profile graphic [17].Antiradical activity. Preparation of extract. Toprepare the extract, 100 mg of a defatted powderedmuffin (muffins defatted with hexane were dried in theoven at 40°C and powdered in a porcelain container)was mixed with 1 mL of 80% methanol in an Eppendorftube. The extraction was performed in the orbital shakerfor 2 h at 25°C followed by centrifugation at 500×gfor 15 min. Supernatants were pooled in an emptyEppendorf tube for antiradical analysis.DPPH assay. Free radical scavenging of the muffinsamples was determined according to the methoddescribed by Uswa and Rabia, with slight modification[18]. 100 μL of a muffin extract was added to3.9 mL of the DPPH solution (2.4 mg of DPPH in 100 mlof 80% methanol) and vortexed thoroughly. Themixture was then incubated for 30 min in the darkand the absorbance was read at 515 nm by using aspectrophotometer against 80% methanol as the blank.The control was 3.9 ml of DPPH + 100 μL of the solvent.A calibration curve of trolox was plotted, with the resultexpressed in μM trolox equivalent/mg of the sample.Sensory evaluation. The overall acceptability of thefortified muffins was evaluated on the 9-point hedonicscale [19]. Muffin samples were given randomly to apanel of 100 untrained volunteers from Guru Nanak DevUniversity, Amritsar (India). They were requested toscore their appreciation from extremely unpleasant (1)to extremely pleasant (9) based on color, odor, texture,taste, and overall assessment. The panelists were alsoasked to rinse their mouths with water before tastingeach sample.Data management and statistics. The results wereanalyzed with Statgraphics Plus program Version 2.1.Data were presented as mean values of triplicatereading ± standard deviation subjected to one-wayanalysis of variance (ANOVA). Tukey test was used tocompare the means, and a significant difference wasdetermined at P ˂ 0.05.RESULTS AND DISCUSSIONTable 2 shows the physical properties of the muffinsfortified with Dacryodes macrophylla L. We observedthat the baking loss in the eggless muffins (9.00–9.56%)was statistically the same but significantly (P ˂ 0.05)lower than in the muffins with eggs (11.22–11.67%).Similarly, the moisture content in the muffins witheggs was higher than in the eggless samples. This44Ndinchout A.S. et al. Foods and Raw Materials, 2022, vol. 10, no. 1, pp. 27–39might be related to the weaker dough consistency of themuffins with eggs, leading to higher viscosity. When theviscoelasticity of dough is high, air bubbles incorporatedduring the creaming step of preparation tend to increaseand rise to the surface of the muffin, getting lost at thebeginning of baking. Moreover, carbon dioxide andvapor pressure produced during baking might escapeand increase the baking loss and moisture content.Larger cells also increase baking loss and usuallyquicken moisture migration during baking [20].Specific gravity gives general information aboutair bubbles that are incorporated in the dough duringmixing and have a direct effect on the muffin height.Higher specific gravity means less incorporation ofair and a lower muffin height. We found the specificgravity values for the eggless muffins (1.12–1.14) tobe higher than that for the muffins with eggs (1.03–1.07). Therefore, the height of the eggless muffins waslower (33.97–34.37 mm) that that of the muffins witheggs (41.00–41.40 mm). Table 2 also shows a slightlyhigher specific gravity, and therefore a lower height,in the samples fortified with the D. macrophylla L.fruit extract. These results might be explained by thepresence of eggs which provide the dough with waterand protein (an egg contains 74% of water and 12.8% ofprotein), thereby increasing its viscoelasticity.Another reason might be the amount of airincorporated in the egg-containing dough comparedto the eggless dough. Potential fibers present inD. macrophylla L. fruits might have increased thedough viscosity and consequently decreased air bubbles.Similar results were reported by Rashida et al. andManuel et al. who found that using fibers in bakeryincreased the specific gravity and viscosity of the dough,which might further lead to a lower height and volumeof muffins by obstructing air incorporation duringmixing [5, 17].At the same wavelength, the specific volume of theeggless muffins (1.66–1.70 mL/g) was significantly lowerthan that of the muffins with eggs (2.18–2.36 mL/g).Specific volume indicates the number of air bubblesretained in the final product after baking. The higherspecific volume of the muffins with eggs could beexplained by higher dough viscoelasticity (due to proteinand water from eggs) which might have enhanced theexpansion of air bubbles by carbon dioxide and vaporpressure during baking.Besides, Shevkani and Singh reported thathigher dough viscoelasticity ensured air bubblesstability during baking [21]. They also found that theincorporation of proteins in muffin dough increased thespecific volume and height of the final products. In ourstudy, however, the specific volume of the muffins witheggs was slightly lower due to the D. macrophylla L.fruits extract.Similar results were found by Singh et al. and Prernaet al. who fortified muffins with Jambolan fruit pulpand red capsicum pomace powder, respectively [12, 16].Our results might be justified by the presence of fibersin D. macrophylla L. fruits which might have inhibitedthe expansion of muffin by weakening the abilityof the gluten matrix to retain carbon dioxide duringbaking [13].Water activity (Aw) is an important parameter thatenhances the shelf life of dry foods when their valueis low. It represents free water in the food and can bedefined as a ratio of vapor pressure of the food to thevapor pressure of pure water. The water activity of theeggless muffins (0.81–0.83) was lower than that of themuffins with eggs (0.87–0.90). Consequently, the shelflife of the former samples was higher.In contrast, Table 2 shows a slight decrease in wateractivity of the egg-containing muffins fortified with theD. macrophylla L. fruit extract. It might be attributed tofibers in D. macrophylla L. fruits absorbing more waterand thereby reducing unbound water in muffins.Moisture, fat, and ash contents (Table 2) in thecontrol muffins with eggs (25.33, 18.61, and 1.27) weresignificantly higher than those in the control egglesssamples (19.17, 16.82 and 1.07). Higher moisture mightbe attributed to egg yolk phospholipids acting asemulsifiers and thereby holding moisture in emulsifiedform.Similarly, the increment of fat and ash in the controlmuffins with eggs may be due to the inherent presenceof fat and minerals in the egg. The incorporation ofTable 2 Physical properties of muffins with Dacryodes macrophylla L. extractPhysical properties Eggless muffins Egg-containing muffinsControl 1% DME 0.5% DME Control 1% DME 0.5% DMEBaking loss, % 9.00 ± 0.33a 9.56 ± 0.48a 9.11 ± 0.11a 11.67 ± 0.19b 11.22 ± 0.11b 11.56 ± 0.29bSpecific gravity 1.12 ± 0.00c 1.14 ± 0.00d 1.13 ± 0.00d 1.03 ± 0.00a 1.07 ± 0.00b 1.06 ± 0.00bSpecific volume, mL/g 1.70 ± 0.03a 1.66 ± 0.01a 1.69 ± 0.02a 2.36 ± 0.01d 2.18 ± 0.01b 2.27 ± 0.01cWater activity, Aw 0.83 ± 0.00a 0.81 ± 0.00a 0.82 ± 0.00a 0.90 ± 0.00c 0.87 ± 0.00b 0.89 ± 0.00cMoisture, % 19.17 ± 1.64a 19.67 ± 0.73a 19.33 ± 0.88a 25.33 ± 0.44b 26.00 ± 1.04b 25.50 ± 0.76bCrude fat, % 16.82 ± 0.13a 16.84 ± 0.46a 16.82 ± 0.22a 18.61 ± 0.34b 18.63 ± 0.24b 18.63 ± 0.31bHeight, mm 34.37 ± 0.50a 33.97 ± 0.30a 34.23 ± 0.27a 41.40 ± 0.35b 41.00 ± 0.21b 41.33 ± 0.33bValues are mean ± standard deviation of triplicate experiments. The values carrying the same letter on the same row are not statistically significant(P ≥ 0.05)45Ndinchout A.S. et al. Foods and Raw Materials, 2022, vol. 10, no. 1, pp. 27–39D. macrophylla L. did not have any significant effecton moisture or fat, although it slightly increased the ashcontent. These results might be due to lower fat and ashcontents in D. macrophylla L.Furthermore, the mineral content (Table 3) in thecontrol muffins with eggs was higher than that inthe control eggless muffins, particularly phosphorus,sodium, potassium, and zinc, which showed a significantdifference. This result was expected because of theinherent presence of minerals in the egg. Also, bothsamples clearly illustrated the enhancement of mineralsin the muffin fortified with the D. macrophylla L.extract, thereby showing this extract as a rich source ofminerals.Our results were in line with those found by Sheetalet al., who reported increased mineral contents inmuffins fortified with dried Moringa Oleifera [1].The rheology parameters of muffin dough s arepresented in Table 4 as G’, G’’, and tan δ, where G’(storage modulus) represents dough elasticity meaning asolid-like behavior, G’’ (loss modulus) represents doughviscosity meaning a liquid-like behavior, and tan δ (ratioof G’’ over G’) tends to zero for solids and to infinity forliquids.We observed that the storage modulus of all doughswas greater than the loss modulus, indicating a typicalelastic dough behavior required for good qualitymuffins. Besides, Nazanin and Mostafa reported thatthe viscosity of cake dough should be optimum to holdair bubbles in the final product, since too low doughviscosity inhibits air incorporation and too high doughviscosity inhibits expansion of air bubbles [22].In our study, the control muffin with egg exhibitedthe highest tang δ, indicating very soft gel dough. Ascan be seen in Table 4, the moduli of the eggless doughswere lower than the moduli of the doughs made witheggs. This was due to the functional role of an egg as agood emulsifier increasing dough viscoelasticity.The moduli G’ and G” increased both for theeggless and egg-containing muffins fortified with 1%D. macrophylla L. This might be attributed to thecapacity of potential fibers in D. macrophylla L. toabsorb water in the dough, thereby lowering the freewater level available to facilitate the movement ofparticles in the matrix. The direct consequence of thisprocess was higher dough viscoelasticity. This findingwas also supported by Jantinder et al. and Felicidadet al. who found that adding proteins and Jambolanfruit pulp increased muffin dough viscosity andviscoelasticity, respectively [16, 23].The color of bakery products is one of the mostimportant parameters that influences consumers’purchasing choices. Crumb color highly depends onthe formulation ingredients, as well as the duration andtemperature of baking, whereas crust color depends oncaramelization and Maillard reactions.The color data for our muffins are given in Table 5as L*, a*, b* and DE corresponding to lightness,redness, yellowness, and different color. We observedthat the L* and a* values of crumb and crust color forthe control muffins with egg were slightly lower thanthose for the control eggless muffins but the differencewas not significant (P ≥ 0.05). However, the b* value ofthe control muffins with egg was higher than that of theTable 3 Mineral and ash contents of muffins fortified with Dacryodes macrophylla L. extractComponent Eggless muffins Egg-containing muffinsControl 1% DME 0.5% DME Control 1% DME 0.5% DMECa, mg/g 3.58 ± 0.53a 5.18 ± 0.53ab 4.38 ± 0.27a 4.11 ± 0.53a 6.79 ± 0.53b 5.72 ± 0.27abMg, mg/g 2.27 ± 0.32a 2.92 ± 0.56a 2.76 ± 0.32a 2.60 ± 0.32a 3.90 ± 0.56a 3.73 ± 0.43aP, mg/g 0.66 ± 0.13a 0.87 ± 0.01abc 0.83 ± 0.02ab 1.00 ± 0.02bc 1.11 ± 0.02c 1.05 ± 0.02bcNa, mg/g 5.03 ± 0.03a 7.19 ± 0.01d 5.82 ± 0.02b 5.93 ± 0.06b 7.75 ± 0.01e 6.75 ± 0.02cK, mg/g 1.52 ± 0.02a 3.61 ± 0.01d 2.40 ± 003b 2.88 ± 0.11c 5.36 ± 0.03f 3.87 ± 0.05eZn, ×102mg/g 0.39 ± 0.03a 1.53 ± 0.08bc 1.13 ± 0.09b 1.67 ± 0.31c 3.36 ± 0.06e 2.45 ± 0.21dAsh, % 1.07 ± 0.07a 1.12 ± 0.06ab 1.11 ± 0.06ab 1.27 ± 0.03ab 1.34 ± 0.03b 1.29 ± 0.05abValues are mean ± standard deviation of triplicate experiments. The values carrying the same letter on the same row are not statistically significant(P ≥ 0.05)Table 4 Rheology parameters of muffins with 1% of Dacryodes macrophylla L. extractRheology parameters Eggless muffins Egg-containing muffinsControl 1% DME 0.5% DME Control 1% DME 0.5% DMEG’ 103.90 ± 9.38a 120.90 ± 9.39a – 664.00 ± 22.62b 804.00 ± 23.13c –G’’ 41.00 ± 3.56a 42.29 ± 3.13a – 286.11 ± 7.47b 299.9 ± 8.02b –Tang delta 0.39 ±0.03a 0.35± 0.031a – 0.43± 0.01b 0.37± 0.01a –Values are mean ± standard deviation of triplicate experiments46Ndinchout A.S. et al. Foods and Raw Materials, 2022, vol. 10, no. 1, pp. 27–39control eggless muffins. This result could be due to eggprotein enhancing the Maillard reaction by providingamino acid which may have reacted with sugars togenerate dark-brown substances, thereby reducing thelightness of the final product, as well as redness [21, 22].However, high yellowness might be attributed to theyellow part of the egg which might have impaired thecolor of the muffin dough. Moreover, incorporating theD. macrophylla L. extract decreased the L*, a*, b* andDE values of the muffins (crumb and crust). This mightbe due to the pigments and polyphenol interacting withother constituents of the dough to impart greenness,thereby darkening the muffin’s color. These results werein line with those reported by Rashida et al. and Marinaet al. who noticed a reduction in the L*, a*, and b* valueswith increased amounts of wheatgrass powder andavocado puree in muffin dough, respectively [5, 24].Since the eggless and egg-containing muffins with0.5% DME were heterogeneous, they were not includedin the color analyses.The textural parameters of the muffins are presentedin Table 6. We found that the eggless muffin (4.68)was firmer than the muffin with egg (3.65). This wasexpected because an egg is a good emulsifier that actsas a plasticizer by increasing dough viscoelasticity andthereby reducing muffin firmness.We also noticed that muffin firmness showed anopposite trend to the specific volume. This was in linewith Nazaninet and Mostafa who concluded that softnesswas improved by both a higher cake volume and theanti-firming effect of the emulsifiers [22]. Furthermore,we found that firmness decreased with the incorporationof D. macrophylla L. This result was consistent withPrerna et al. who reported a decrease in muffin hardnesswith an increase in capsicum pomace [12]. Chewinesscorresponds to the amount of energy required todisintegrate food for swallowing. Chewiness andgumminess of muffins follow the same trend as hardnesssince both parameters are dependent on firmness [17].Springiness is a desirable property indicative of muffinelasticity, since it measures the extent of recoverybetween the first and the second compression. In ourstudy, the springiness values were generally higher(0.68–1.97) than those obtained by Shevkani andSingh who added different protein isolates to muffins(0.64–0.85) [21].The higher springiness of the control muffin with egg(1.97), compared to the control eggless sample (1.27),might be due to egg protein aggregation that improvedthe quality of muffins. However, this textural parameterdecreased with the incorporation of D. macrophylla L.Prerna et al. also reported a decrease in springiness withthe incorporation of capsicum pomace [12].Cohesiveness is the ability of a material to stickto itself. It measures the internal resistance of foodstructure under some compression. We found thecohesiveness value of the control muffin with egg to besignificantly higher (0.29) than that of the control egglessTable 5 Color parameters of muffins with 1% of Dacryodes macrophylla L. extractColor data ColorparametersEggless muffins Egg-containing muffinsControl 1% DME 0.5% DME Control 1% DME 0.5% DMECrust L* 47.67 ± 0.58b 38.17 ± 1.43a – 46.85 ± 0.40b 34.74 ± 1.32a –a* 3.80 ± 0.27d 2.16 ± 0.09c – 0.95 ± 0.03b –0.17 ± 0.03a –b* 22.38 ± 0.15b 19.01 ± 0.49a – 28.55 ± 0.25c 21.76 ± 0.32b –DE 46.56 ± 1.18a 52.24 ± 0.13b – 47.70 ± 1.50a 50.70 ± 0.63b –Crumb L* 69.31 ± 1.13c 46.70 ± 0.30b – 52.36 ± 1.75b 36.21 ± 2.59a –a* 10.33 ± 0.51c 6.73 ± 0.58b – 6.16 ± 0.27b 0.90 ± 0.13a –b* 29.52 ± 0.21c 23.49 ± 0.49b – 38.51 ± 0.16d 18.03 ± 0.89a –DE 40.40 ± 2.72a 57.40 ± 1.80c – 46.22 ± 0.07b 69.62 ± 0.97d –Values are mean ± standard deviation of triplicate experiments. The values carrying the same letter on the same row are not statistically significant(P ≥ 0.05)Table 6 Texture parameters of muffins under studyTexture parameters Eggless muffins Egg-containing muffinsControl 1% DME 0.5% DME Control 1% DME 0.5% DMEHardness 4.68 ± 1.57c 2.96 ± 0.55a 3.03 ± 0.14a 3.65 ± 0.32b 2.61 ± 0.20a 3.01 ± 0.05aAdhesiveness, mJ 0.007 ±0.003a 0.008 ± 0.002a 0.006 ±0.002a 0.022 ± 0.002b 0.031 ± 0.004bc 0.023 ± 0.005bCohesiveness 0.17 ± 0.011a 0.16 ± 0.01a 0.17 ± 0.01a 0.29 ± 0.04b 0.23 ± 0.01ab 0.24 ± 0.01abSpringiness, mm 1.27 ± 0.11ab 0.68 ± 0.04a 0.75 ± 0.24a 1.97 ± 0.45b 1.02 ± 0.14ab 0.84 ± 0.14aGumminess, N 1.35 ± 0.33b 0.63 ± 0.06ab 0.71 ± 0.06ab 1.05 ± 0.21ab 0.48 ± 0.09a 0.52 ± 0.03aChewiness, mJ 3.02 ± 1.14b 0.54 ± 0.15a 0.74 ± 0.15ab 1.38 ± 0.40ab 0.35 ± 0.01a 0.40 ± 0.17aValues are mean ± standard deviation of triplicate experiments47Ndinchout A.S. et al. Foods and Raw Materials, 2022, vol. 10, no. 1, pp. 27–39muffin (0.17). This result might be attributed to the eggprotein network along with starch gel that might haveimpacted the muffin crumb texture [21].Nevertheless, there was no significant differencein cohesiveness and adhesiveness values in the muffinsfortified with D. macrophylla L. Our results were inagreement with those found by Maria et al. who reportedno significant differences in cohesiveness values amongfiber-enriched bake products (squash seed flour) [20].Overall, hardness, chewiness, gumminess, andspringiness decreased with the incorporation ofD. macrophylla L., whereas cohesiveness andadhesiveness did not show any significant difference.However, the muffins with egg had lower hardness,chewiness, and gumminess and higher springiness,cohesiveness, and adhesiveness compared to the egglessmuffins.The total phenolic content assay determines bothbound and unbound phenolics, while the radicalscavenging activity assay measures free antioxidants.Thus, the latter is more efficient at preventing thereactive oxygen species from attacking lipoproteins,polyunsaturated fatty acids, DNA, amino acids, andsugars because it describes the capacity of an antioxidantin both food and biological systems [25].Therefore, we used DPPH, a stable free radical, toevaluate the antioxidant capacity of our fortified muffins(Table 7). We found that the DPPH inhibition valuesfor both eggless muffins and those with eggs increasedsignificantly with the incorporation of D. macrophyllafruit. This result may be attributed to antioxidantcompounds in D. macrophylla fruit increasing theDPPH activity.Our results were consistent with those found byother authors who reported better DPPH activity withhigher levels of Jambolan fruit pulp in the gluten-freemuffins [11, 16].The results of sensory evaluation of the muffinsamples are presented in Table 8. The overallacceptability ranged from 5.3 to 7.9, meaning that themuffins were considered slightly or moderately pleasantaccording to the 9-point scale, except for the samplescoring 5.3 (neither unpleasant, nor pleasant).The egg-containing muffins with 1% of DMErecorded the lowest score (5.3) and was considered notacceptable because its acceptance index (59%) was lowerthan 70% (Table 9). This low score resulted from thesample’s taste, which also had the lowest score. Mostpanelists considered its taste unpleasant, indicatingbitterness after swallowing.In contrast, the control egg-containing muffinsreceived the highest overall acceptability score (7.9) andthe highest acceptance index (87.88%). However, wefound no significant difference with the control egglessmuffin or the egg-containing muffin with 0.5% DME.The highest score of the control egg-containing muffinmight be attributed to its texture, which was ratedTable 7 DPPH assay: Antiradical activity of muffins with Dacryodes macrophylla L. extractRadical Scavenging Activity Eggless muffins Egg-containing muffinsControl 1% DME 0.5% DME Control 1% DME 0.5% DMEDPPH, μM troloxeq/mg 3.90 ± 0.52a 6.84 ± 0.93bc 5.06 ± 0.19abc 4.57 ± 0.26ab 7.85 ± 0.96c 6.22 ±0.30abcValues are mean ± standard deviation of triplicate experimentsTable 8 Sensory indicators of muffins under studySample Color Odor Texture Taste Overall acceptabilityEggless muffinsControl 7.9 ± 0.1cd 7.7 ± 0.1c 7.4 ± 0.1c 7.7 ± 0.1cd 7.7 ± 0.1c1% DME 6.6 ± 0.1b 7.1 ± 0.1b 6.6 ± 0.1a 7.2 ± 0.1c 6.9 ± 0.1b0.5% DME 7.1 ± 0.1c 6.9 ± 1.0b 6.8 ± 0.1ab 6.4 ± 0.1b 6.6 ± 0.1bEgg-containing muffinsControl 7.9 ± 0.1cd 7.6 ± 0.1c 8.2 ± 0.1d 7.8 ± 0.1d 7.9 ± 0.1c1% DME 6.1 ± 0.1a 6.3 ± 0.1a 7.1 ± 0.1bc 4.6 ± 0.2a 5.3 ± 0.1a0.5% DME 7.5 ± 0.1c 7.6 ± 0.1c 8.0 ± 0.1d 7.8 ± 0.1d 7.7 ± 0.1cValues are mean ± standard deviation of triplicate experiments. Values carrying the same letter in the same column are not statistically significant(P ≥ 0.05)Table 9 Acceptance index and acceptability among muffinsamplesSample Acceptanceindex, %Acceptability, %Like DislikeEggless muffinsControl 86.00 101 (100.0) 0 (0.0)1% DME 77.11 89 (88.12) 12 (11.88)0.5% DME 73.33 83 (82.18) 18 (17.82)Egg-containing muffinsControl 87.88 101 (100.0) 0 (0.0)1% DME 59.22 44 (43.56) 57 (56.44)0.5% DME 85.55 98 (97.03) 3 (2.97)A product is acceptable when its acceptance index is greater than 70%48Ndinchout A.S. et al. Foods and Raw Materials, 2022, vol. 10, no. 1, pp. 27–39highest (8.2). Its appreciation by the panelists was inagreement with its springiness and specific volume (1.97and 2.36, respectively), also scored highest.The incorporation of D. macrophylla L. fruitstended to lower the average acceptance scores bothfor the eggless muffins and for those with eggs. Thesame trends were observed by Abdessalem et al. whointroduced date fiber concentrate in muffins [13]. Inour work, the egg-containing muffins with 0.5% DMEhad the best rank among the samples and received thesame rank as the controls (both with and without egg).This means that the panelists preferred the muffins withD. macrophylla L. extract to the eggless control muffins.CONCLUSIONOur results revealed that the incorporation ofDacryodes macrophylla L. fruit decreased wateractivity, the L*, a*, and b* values, as well as the firmnessof the muffins, whereas no prominent difference wasobserved in their baking loss, height, moisture, fat,cohesiveness, springiness, gumminess, or chewiness.In contrast, D. macrophylla L. increased specificgravity, changed rheology, and tended to increaseadhesiveness, antioxidant activity, and mineral contents(particularly Na and K) of the muffins. Anotherinteresting result was that the panelists statisticallyaccepted the muffins with 0.5% of DME, scoring themin the same range as the control ones.Therefore, D. macrophylla L. fruit is a good potentialingredient to develop new bakery products rich inminerals and antioxidants but further investigationsneed to be done to improve the color acceptance ofmuffins and to determine the optimal concentration ofD. macrophylla L.CONTRIBUTIONA.S. Ndinchout, V. Kaur, and N. Singh conceived,designed, and performed the study, collected thedata, and wrote the manuscript. D.P. Chattopadhyay,M.A. Nyegue, and F.P. Moundipa contributed to the dataanalysis and proofread the manuscript.CONFLICTS OF INTERESTThe authors declare that there is no conflict ofinterest regarding the publication of this paper.ACKNOWLEDGMENTSWe thankfully acknowledge the financial support inthe form of fellowship and cooperation in each step ofthis doctoral research provided by the Organization forWomen in Science for Developing World (OWSD), Italyand the Swedish International Development CorporationAgency, which helped us to complete the work. We arealso thankful to the staff and students at Guru NanakDev University, Amritsar (India) and Dr. Saha FoudjoBrice, University of Bamenda, Cameroun for their helpand cooperation during sensory evaluation