Walnut Flour Research Articles

Production, Nutritional Evaluation and Acceptability of Cookies Made from a Blend of Wheat, African Walnut, and Carrot Flours

Cookies were developed from composite flour of wheat, African Walnut and Carrot. The wheat flour was substituted at levels of 5%, 10%, 15%, & 20% with African Walnut flour for samples, B, C, D and E, respectively, and with 5% of Carrot flour. The moisture content of the cookies reduced with increase in substitution with walnut flour and carrot flour but there was no significant difference (p>0.05) in the values obtained. The ash content and protein content of the cookies also increased with increased substitution whereas fat content of the substituted cookies samples increased and significantly differed (p˂ 0.05) from the control. The physical attributes are as follows:11.28 g - 13.09 g for Weight, 45.80 mm - 52.68 mm for Diameter, 6.85 mm - 9.45 mm for thickness, and 5.12 - 7.44 for spread ratio. The values of the Minerals obtained are 29.38 mg/100 g – 50.46 mg/100 g, 3.75 mg/100 g – 11.36 mg/100 g, 14.11 mg/100 g – 15.47 mg/100 g and 49.20 mg/100 g – 58.90 mg/100 g for Calcium, iron, Sodium, and Potassium, respectively. The Bioavailability was highest in sodium(57.07%-84.86%), and potassium(69.55% - 72.31%).The highest values for Vitamin C (13.85 mg/100 g), Vitamin E (0.90), and Invitro protein digestibility (59.64%) were recorded in sample E while the highest Carotenoids (257.40 mg/100 g) was observed in sample C. Sensory evaluation confirmed that there was no significant difference (p˃0.05) between Samples A (control sample) and the substituted samples in terms of appearance, taste and aroma, and although sample A had highest overall general acceptability value, the samples produced compared favorably with the control.

About the possibility of modifying the recipe of bread «fitness» buckwheat by using walnut flour

Walnut flour is considered by food technology specialists as a source of complete protein, lipids, carbohydrates, minerals, vitamins, etc. The purpose of the research is to study the possibility of using walnut flour in the “Fitness” buckwheat bread technology in order to expand the range and increase the nutritional density of bakery products. The objects of research were: baking wheat flour of the first grade; walnut flour; bakery mix “Fitness Mix” buckwheat; control samples of “Fitness” buckwheat bread; experiment No 1 – replacing 15 % of wheat flour with an identical amount of walnut flour; experiment No 2 – with the replacement of 15 % of wheat flour with walnut flour and the replacement of 2 % of the bakery mixture with a similar amount of wheat gluten; experiment No 3 – with the replacement of 15 % of wheat flour with walnut flour and replacement of 4 % of the bakery mixture with wheat gluten; experiment No 4 – with the replacement of 15 % of wheat flour with walnut flour and the replacement of 6 % of the bakery mixture with wheat gluten. The quality and chemical composition of wheat flour, walnut flour and a mixture of bakery buckwheat were investigated. The superiority of walnut flour over wheat raw materials in terms of a number of nutrients was revealed. The priority role of wheat flour in the formation of porosity and the formation of the specific volume of bread is determined. Modification of the “Fitness” buckwheat bread recipe was carried out.

Functional components of non-traditional raw materials in the design of bakery products

Wheat bread remains in the diet not only of Russians, but also of the population of other countries as a daily product, which makes it possible to consider it as an object for modifying the chemical composition and nutritional value in order to give it functional, dietary, or therapeutic and prophylactic properties. The purpose of the research is to study the composition of the functional components of non-traditional types of flour used in wheat bread technology in order to establish the effectiveness of their use. The objects of research were: bakery wheat flour of the highest grade, walnut flour, peanut flour, coconut flour. The analysis of organoleptic, physicochemical indicators and nutritional value of wheat bakery flour and various types of flour from walnut is carried out. An acceptable sensory compatibility of the studied raw material was established. Replacing a part of wheat flour in the recipe of bakery products with raw materials from peanuts or walnuts is a reasonable condition for eliminating the deficiency of dietary fiber in them. Increasing the biological value of products and the content of polyunsaturated fatty acids in it due to the use of peanut and coconut flour is of undeniable nutritional value. The source of phosphorus and copper can be considered flour from walnuts and peanuts; iron and selenium – walnut and coconut flour; magnesium and calcium – walnut flour. In a practical way, the effectiveness of replacing wheat flour in the recipe of bakery products with raw materials from nut-bearing raw materials has been established to increase the content of functional food ingredients in finished products.

The use of walnut flour in the recipe of "Fitness" buckwheat bread

The use of walnut flour in the recipe of "Fitness" buckwheat bread

Solubility and emulsifying properties of phosphorylated walnut protein isolate extracted by sodium trimetaphosphate

Low solubility and poor emulsifying properties of walnut protein isolate (WPI) greatly influences its applications in the food industry. In the current work, WPI was extracted and phosphorylated from defatted walnut flour by sodium trimetaphosphate (STMP) at various pH values (7.0, 9.0, and 11.0). The measured phosphorus content of STMP-extracted WPI was approximately 7-10-fold higher than that of the alkaline-extracted WPI (A-WPI). The results of X-ray photoelectron spectroscopy (XPS) and Fourier transform infrared spectroscopy (FTIR) further confirmed the successful phosphorylation of extracted WPI. Conformational studies using FTIR and circular dichroism (CD) indicated that phosphorylated WPI (P-WPI) contained higher α-helical and lower β-sheet contents than the A-WPI. Phosphorylation of WPIs altered the surface hydrophobicity and surface charges of the proteins, resulting in a significant improvement in the solubility of P-WPI. In addition, the emulsifying properties of P-WPI were significantly enhanced, which was exhibited by a 2.5-4-fold increase in the emulsifying activity index (EAI) and a maximum 6-fold increase in the emulsifying stability index (ESI). The emulsions stabilized by P-WPI manifested relatively smaller sizes and larger surface charges. This study demonstrated that phosphorylation modification can effectively modulate the surface hydrophobicity and charges of WPI to greatly improve its solubility and emulsifying ability.

Assessing the quality of fried bean cake made from blend of cowpea and walnut flours

Assessing the quality of fried bean cake made from blend of cowpea and walnut flours

Improving walnuts' preservation by using walnut phenolic extracts as natural antioxidants through a walnut protein-based edible coating.

Walnut kernels contain high amounts of polyunsaturated fatty acids that determine a limited shelf life on these nuts. The application of walnut phenolics as antioxidants through a walnut protein-based coating, obtained from walnut oil cake residue, can help to increase the shelf life of walnuts. The objective was to evaluate the preservative effect of walnut polyphenols included in a walnut-proteic edible coating on walnut kernels. Three treatments of walnuts coated with walnut flour were prepared: without the addition of antioxidants (control); with the addition of a walnut phenolic extract; and with the addition of butylated hydroxytoluene (BHT). On the last storage day, the sample with the addition of walnut phenolics presented a lower peroxide (3.64 meq 02 /kg oil) and anisidine value (1.11), conjugated diene (15.92), and hexanal content (19.67× 106 e.c.) than the control sample (6.23, 1.81, 24.65, and 122.37× 106 e.c., respectively). Also, on the last day, the control sample showed the highest deterioration of polyunsaturated fatty acids (from 74.83 to 71.08g/100g),carotenoid (from 3.43 to 1.90mg/kg), and γ-tocopherol content (from 349.66 to 298.42mg/kg). In addition, this sample exhibited the highest oxidized (20.33) and the lowest walnut flavor intensity (64.67) on day 84. Regarding consumer acceptance, the phenolic-added sample displayed a greater flavor acceptance score. Walnut phenolics, implemented through a walnut protein-based coating, improve the preservation of walnuts. PRACTICAL APPLICATION: The combination of walnut-phenolic extracts and walnut-based edible coating applied on walnuts by food industries allows to prolong their shelf life, by preserving their nutritional, sensory, and quality properties. Considering the practical feasibility, the procedure used to prepare these products is simple and requires machineries already present in food industries. In addition, the utilization of this coating with walnut-phenolics exerts benefits like, the prevention of allergen cross-contamination in the chain of production, the utilization of an industry's residue, the replacement of synthetic antioxidants and, and the diminishment of the amount and thickness of plastic needed for walnuts' packaging.

Influence of walnut on the nutritional and physicochemical properties of biscuits made from whole wheat

In this study, the influence of walnut flour in biscuit production was studied. Biscuits were made from blends of whole wheat with walnut flours and were assessed for quality attributes and storability. Walnut was blended with whole-wheat thus: B (2%:98%); C (4%:96%); D (6%:94%); E (8%:92%) and F (10%:90%), while plain whole wheat flour served as control (Sample A). The biscuits were baked in the oven operated at 1800C for 20-30 minutes, cooled, packaged, stored for eight weeks, and analysed for physicochemical, microbial and sensory properties using standard methods. The results revealed that the proximate composition of the samples during storage were as follows: protein, moisture, ash, crude-fat, crude-fibre and carbohydrate values ranged thus: (9.30-14.26%), (10.28-12.06%), (2.20-2.92%), (13.24-16.66%), (0.69-1.17%) and (53.60-61.47%) respectively, with better nutrient stability in the treated samples when compared to the control. The colour varied with increasing substitution, while the essential amino acids were higher in the walnut-supplemented samples. The microbial load of the control was higher than those of the treated samples, due to high antioxidant activity of walnut. Sensory evaluation revealed that biscuit sample having 2% walnut flour was most preferred.
 Keywords: Whole wheat flour; walnut; proximate composition; antioxidant properties; shelf life.

Proximate Composition, Sensory Properties and Microbial Quality of Chin-chin Developed from Wheat and African Walnut Flour Blends for Household Food Security

Objective: The objective of this study was to investigate the proximate composition, sensory properties and microbial quality of chin-chin developed from wheat and African walnut flour blends as a means of achieving household food security.
 Methodology: African walnut was processed into flour. Chin-chin was prepared from blends of wheat and African walnut flours using 90:10, 80:20, 70:30, 60:40, 50:50 of wheat flour to African walnut flour (AWF), and 100% wheat flour as control. Samples were subjected to sensory evaluation within 30 min of production. Proximate analysis was carried out using standard methods. The samples were also stored for 3 weeks and evaluated at weekly intervals for total bacterial and fungal counts.
 Results: composition of the chin-chin revealed a significant (p<0.05) increase in ash (0.42-1.38%), fat (34.39-40.03%), crude protein (5.53-7.95% protein), crude fibre (0.98-1.86%), and energy contents (402.65-414.08kcal) with a decrease in moisture (3.31-4.85%) and carbohydrate (45.59-53.84%) . Sensory analysis of the chin-chin showed that the control chin-chin was more preferred than all other samples. This was followed closely by chin-chin substituted with 10% African walnut flour having mean scores above 6 for all sensory attributes. Total bacterial counts (TBCs) and fungal counts (TFCs) of the chin-chin samples were observed to increase during storage. TBCs and TFCs of chin-chin samples after 3 weeks of storage ranged from 6.00×103-8.50×103cfu/g and 6.80×103-8.00×103cfu/g, respectively. The samples presented adequate microbiological conditions and were within recommended safe limit of microbial guidelines.
 Conclusion: The findings of the study showed that chin-chin of acceptable sensory attributes and improved nutritional content could be produced with up to 10% African walnut flour (AWF) level. In effect, chin-chin substituted with African walnut flour can be consumed by households thereby improving their nutritional status and eradicating food insecurity and malnutrition which is common among households.

Evaluation of blends of wheat (Triticum aestivum) flour and African walnut (Tetracarpidium conophorum) flour in biscuit production

The use of underutilized crops has been the focus of recent research in developing countries like Nigeria because of inadequacy of protein supply in diets. In attempt to improve the use of underutilized crops, biscuit samples were produced from flour blends containing different combinations of African walnut flour and wheat flour. The 100% wheat flour served as control. The African walnut and wheat flours were mixed in ratios 10:90, 20:80, 30:70, 40:60 and 50:50%. The proximate composition, functional and pasting properties of the blends as well as physical and sensory properties of the biscuits were determined The results showed the increase in the level of protein, ash, fat and moisture content of the blends with increasing levels of walnut flour. The bulk density, water absorption and swelling power of the blends reduced, while oil absorption capacity, emulsion capacity and least gelation concentration increased with increasing levels of walnut flour. Variations exist in the pasting properties of the blends. The diameter of the biscuits increased with increase in the level of walnut flour, hence the spread ratio increased from 3.52 to 6.56. There were significant differences between the biscuit samples in terms of aroma, taste and appearance. However, biscuit sample with inclusion level of 30% walnut flour compared favourably with the control in terms of sensorial quality

Nanocomposite bilayers based on poly(vinyl alcohol) and chitosan functionalized with gallic acid

The development of active bilayer systems is a novel strategy for the application of active packaging to maintain or prolong the shelf‐life of food products. A bilayer system was assembled in situ into a thermocompression unit through a two-step procedure. One of the layers was obtained by a casting process and consisted of a chitosan-based nanocomposite functionalized with gallic acid (GA); the other was shaped by the spreading of polyvinyl alcohol solution on the nanocomposite. Then, a stage of thermocompression formed the bilayer system. In this way, a feasible material with water vapor and oxygen barrier as well as UV barrier properties due to the presence of GA was designed by a thermocompression process which can be industrially scaled representing a technological progress. The formation of the bilayers was corroborated by SEM allowing discerning between both, the PVA layer and the nanocomposite layer. On the other hand, the corroboration of interactions between the layers of the system was carried out through ATR-FTIR and DSC analysis. The system was used as packaging of a food susceptible to undergo oxidation such as walnut flour, generating a delay in the formation of hydroperoxides and secondary oxidation compounds compared with a synthetic container. These results indicated that bilayer materials can be useful for the conservation of this type of foods.

Increase of walnuts' shelf life using a walnut flour protein-based edible coating

The present study aimed to improve walnut quality during storage. An edible coating was developed from defatted walnut flour and applied to the surface of walnut kernels, which were subsequently stored at 40 °C for 84 days along with walnuts coated with methylcellulose and uncoated kernels. On day 84, the walnuts coated with the walnut flour coating presented the lowest oxidized (13.33) and cardboard (34.73) flavors, the highest walnut flavor (72.27), the highest carotenoid (2.01 mg/kg) and γ-tocopherol contents (306.78 mg/kg) and the least deterioration of oleic/linoleic fatty acids ratio. Furthermore, the kernels covered in this coating displayed higher overall consumers' acceptance than those covered with methylcellulose (5.31). The methylcellulose and walnut flour coatings also prevented against polyunsaturated fatty acids’ deterioration, while walnuts coated with methylcellulose displayed a better behavior for peroxide value. Both coatings protected walnuts against the deterioration processes. Walnut flour coating could be used as a natural alternative to prolong the shelf life of walnut kernels, without the introduction of allergens nor synthetic compounds in this food product.

Study of electrochemically treated walnut emulsion and its stability

AbstractThe oil‐containing walnut flour has limited applications since it is easily oxidized and deteriorated. In the present study, walnut cake with a fat content of 16.3% was used as a raw material for by‐products making following an hydraulic process. The walnut cake was crushed to 20 meshes and mixed with water at a ratio of 1:4. The mixtures were ground and filtered. Then, the filtrates were homogenized at 80 MPa pressure. The walnut emulsions were pumped into the solid polymer electrochemical reaction chamber at a speed of 35 mL/min, the temperature was controlled at 60 °C, the current density of the direct current was 0.08 A/cm2, and the time of cycle reaction was 90 min. After electrochemical treatment, the iodine values of fats in walnut emulsions were reduced from 140 to 92 g I2/100 g oil. The nitrogen solubility index of walnut emulsion has improved by 4.6% at 30 °C. Storing the oil‐containing walnut flour for 24 weeks, the peroxide value was reduced to 5.64 meq O2/kg oil compared to the nonelectrochemical treated oil (10.52 meq O2/kg oil). These results indicate that the electrochemical treatment enhances the stability of the oil‐containing walnut flour.Practical applicationsIn the present study, fats from walnut cake were used for by‐products making following a hydraulic process. The electrochemical hydrogenation reduced the iodine values of fats in walnut emulsions. Based on the current funding, the oxidation stability of oil‐containing walnut flour was improved significantly. The trans fatty acids of electrochemical‐treated oil‐containing walnut flour was only 1.6%. A portion of the protein was electrolytically reduced. The nitrogen solubility index of oil‐containing walnut flour increased and improved the quality of the final products. The electrochemical hydrogenation improved significantly the stability of oil‐containing walnut flour and can be further applied for industrial purposes.

The Effect of Walnut Flour on the Physical and Sensory Characteristics of Wheat Bread.

The study was carried out to demonstrate the effect of walnut flour enhancement on the physical, nutritional, and sensory quality of bread. Walnut flour was prepared by soaking, deshelling, oven drying, and sieving whole walnuts. The wheat flour was supplemented with walnut flour by 0, 20, 30, 40, and 50% of the total amount. Standard procedures were taken to estimate the proximate composition of wheat and walnut flour and bread samples. A comparison between the control and supplemented bread was made, where the physical characteristics (weight, volume, and specific volume) and sensory quality were checked. The enhanced bread, where the percentage was between 20 and 50%, appeared to have a significant increase in protein, fat, linoleic acid, and α-linolenic acid and a decrease in carbohydrate and fibre values. Increased walnut flour replacement showed that physical properties, loaf volume and specific loaf volume, have declined. The sensory attributes between the unsupplemented and supplemented bread showed major differences. As an outcome, substituting 30% walnut flour gave the best overall quality of bread acceptability.

Effect of Adding Walnut Powder on Physical and Chemical Properties of Wheat Flour and Preventing Hyperlipidemia in Mice

Walnuts (Juglans regia L.) are naturally rich source of many important nutrients which could be helpful in different food processing. Walnut mainly containing polyunsaturated fatty acids (PUFA), especially alpha linoleic acid (18:3n-3; 9 g) and linoleic acid (18:3n-; 38 g). Walnuts powder was fortified with commercial high gluten wheat flour (WF) into 4 composites flour from 10% to 40%. Walnut flour improves the nutritional value due to high protein and fat content, but affects the technological properties. Parameters such as functional, pasting and rheological properties demonstrated the influence of walnut reincorporation into gluten network. The interaction of walnut flour with wheat flour is a key factor which effects on the dough quality, causing thinning and weakening the gluten structure. Flour with 30% to 40% walnut substitution was more nutritious especially in relation to protein and monounsaturated fatty acid (MUFA), but responsible for more changes in technological characteristics of dough. Present study was also directed to examine the effect of moderate walnut consumption on lipids profile, enzymatic anti-oxidant (superoxide dismutase SOD and glutathione peroxidase GSH-Px) and lipid peroxidation (Melondialdehyde MDA) in rats fed with high-fat food. The Sprague Dawley rats were housed for five weeks and assembled into normal, high fat, high fat (HF) + 10% walnut, HF + 20% walnut, HF + 30% walnut and HF + 40% walnut. The lipid profile significantly improved especially by lowering the low-density lipoprotein cholesterol (LDL-c) and high-density lipoprotein cholesterol (HDL-c) level increased in the group of HF + 40% walnut. The total anti-oxidant, SOD and GSH-Px activity were increased by supplementation of walnut and significantly higher in HF + 40% compared to the normal group. The Melondialdehyde (MDA) or lipid peroxidation status was increased in HF + 20% walnut to HF + 30% walnut as compared to normal and HF-fed diet but reduced by HF + 40% walnut. These results suggest that walnut intake could be effective to protect from oxidative stress by lowering the lipid peroxidation by improving antioxidant defense system in rats fed high-fat diet.

Evaluation of Biscuit Produced from Composition of Wheat and Africa Walnut Flour

Evaluation of Biscuit Produced from Composition of Wheat and Africa Walnut Flour

Effect of genotype and crop year on the nutritional value of walnut virgin oil and defatted flour

The present study analyses the health-promoting compounds of walnut oil and walnut defatted flour obtained using hydraulic pressing. To identify the cultivar effect, nine walnut varieties were harvested in the same plot for two years to control environmental and agricultural management effects on kernel chemical traits. Beyond the variability reported in the products obtained from the different cultivars analysed, the crop year showed a crucial effect in the nutritional value of walnut products. Specifically, the variability caused for the crop year in the concentration of oleic and linoleic acids, phytosterols, polyphenols, tocopherols, proteins and essential minerals (K, Mg, P, S, Cu, Fe, Mn, Mo, Ni) was greater that the reported for the genotype. These findings suggest that the nutritional value of walnut oil and walnut flour depends on the crop season largely than expected, even when average annual weather conditions are similar. As a result, focus must change in the study of cultivar effect on walnut products to a wider analysis of specific variables related to crop year conditions.

Effect of extraction methods on structural, physiochemical and functional properties of dietary fiber from defatted walnut flour.

The effect of different extraction methods i.e. extraction with alkali (AEDF), enzyme (EEDF) and enzyme plus shear emulsifying hydrolysis (SEDF) on structure, physiochemical as well as the functional characteristics of dietary fiber (DF) from defatted walnut flour were studied. AEDF process showed significantly higher (P<0.05) amount of water retention capacity (WRC; 5.39g/g), water swelling capacity (WSC; 3.16g/mL), and particle size; while, shown lower value of oil adsorption capacity (OAC; 29g/g) amongst all. Compared to AEDF, no major differences were observed in network except the matrix in EEDF and SEDF was more porous and honey comb like. DF extracted through AEDF, EEDF and SEDF showed good viscosity and emulsifying activity however, less stability indices. The results from this study suggest that AEDF and EEDF and SEDF had specific effects on the structure-functional properties of DF from defatted walnut flour, which has great potential in food applications.

Optimization of simultaneous microwave/ultrasonic-assisted extraction of phenolic compounds from walnut flour using response surface methodology

Context: Walnut is a traditional food as well as a traditional medicine recorded in the Chinese Pharmacopoeia; however, the large amounts of walnut flour (WF) generated in walnut oil production have not been well utilized. Objective: This study maximized the total polyphenolic yield (TPY) from the walnut flour (WF) by optimizing simultaneous ultrasound/microwave-assisted hydroalcoholic extraction (SUMAE). Materials and methods: Response surface methodology was used to optimize the processing parameters for the TPY, including microwave power (20–140 W), ultrasonic power (75–525 W), extraction temperature (25–55 °C), and time (0.5–9.5 min). The polyphenol components were analysed by LC–MS. Results: A second-order polynomial model satisfactorily fit the experimental TPY data (R 2 = 0.9932, P < 0.0001 and R adj 2 = 0.9868). The optimized quick extraction conditions were microwave power 294.38 W, ultrasonic power 93.5 W, temperature 43.38 °C and time 4.33 min, with a maximum TPY of 34.91 mg GAE/g, which was a rapid extraction. The major phenolic components in the WF extracts were glansreginin A, ellagic acid, and gallic acid with peak areas of 22.15%, 14.99% and 10.96%, respectively, which might be used as functional components for health food, cosmetics and medicines. Discussion and conclusion: The results indicated that walnut flour, a waste product from the oil industry, was a rich source of polyphenolic compounds and thus could be used as a high-value functional food ingredient.

Molecular Characterization, Antioxidant and Protein Solubility-Related Properties of Polyphenolic Compounds from Walnut (Juglans regia)

Aqueous ethanol extraction of partially defatted walnut flours provides a simple and reliable method to obtain extracts with high content of polyphenolic compounds. These were characterized by means of HPLC-ESI-MS/MS analytical techniques and molecular parameters. Considering the whole set of polyphenolic compounds identified, a high average number of phenolic-OH groups was found. Although these represent potential hydrogen-atom transfer sites, which are associated with high free-radical scavenging capacity, results show that such a property could be strongly limited by the low lipophilicity of polyphenols affecting the accessibility of these molecules to lipid substrates. Variations in pH values were found to change the ionization behavior of phenolic compounds. These changes, however, had minor effects on walnut protein solubility-related properties. The results obtained in this study highlight the importance of molecular characterization of walnut phenolic compounds in order to assess better their bioactive properties.