Rheological behaviour, physical and sensory properties of orange fleshed sweet potato and soy concentrate bread.

Trends on the use of non-wheat flours for bread production has led to researches on improving the rheological characteristics of such non-wheat flours. This aim of this study was to determine the effect of soy concentrate on the protein and rheological behaviour (pasting and mixolab) of the orange-fleshed sweet potato composite flour as well as the physical and sensory qualities of the bread produced. The experimental design to obtain the optimum blends was carried out using optimum design of response surface methodology; with sweat potato, soy bean concentrate, date palm flour and potato starch as the independent variables. The result shows that protein values ranged from 6.19 to 21.10%, carotenoid values ranged from 0.11 to 26.18 mg/100 g. pasting temperature ranged from 68.50 to 82.33 °C; peak viscosity ranged between 159 and 1040 RVU, the breakdown value ranged between 24 and 272 RVU and the setback value ranged from 75 to 368 RVU. The bread loaf weights ranged from 111 to 256 g and the specific loaf volume ranged from 0.7 to 1.6cm3/g. The bread samples varied significantly (p < 0.05)  with the consumer's acceptability in terms of aroma, appearance, taste and overall acceptability. It was observed that soy-concentrate increase the protein content and improves rheological properties of the composite flour for the production of gluten free bread.

Biochemical and antioxidant properties of cream and orange-fleshed sweet potato.

The rate of micronutrient deficiency has been on an increase since the last decade and the utilization of bio-fortified crops could help to alleviate this deficiency and food insecurity in Africa especially in Nigeria. The aim of this study was to compare the biochemical and antioxidant properties of cream-fleshed and orange-fleshed sweet potato. The varieties of OFSP used in this study were mother's delight (MDP) and king J (KJP) orange-fleshed sweet potato while the other variety was cream-fleshed sweet potato (CFSP). The tubers were processed into flour and analyzed for proximate, minerals, anti-nutrient and antioxidant properties using standard methods. The ash content ranged from 4.60 to 7.20%, carbohydrate content ranged between 73.47 and 78.61%. MDP has the highest beta carotene content with 18.83 mg/100g followed by KJP and CFSP. Magnesium value ranged between 124.0 and 148.2 mg/100g, potassium ranged from 1226.5 to 2350.0 mg/100g. Sodium-potassium ratio (Na/K) was <1. The antioxidants properties evaluated were all higher in OFSP than CFSP. The bio-fortified sweet potato showed an improved biochemical and antioxidant properties compared to the CFSP, thus OFSP will be suitable to combat micronutrient deficiency and food insecurity in Africa.

Orange-fleshed sweet potatoes composite bread: A good carrier of beta (ß)-carotene and antioxidant properties.

Orange-fleshed sweet potato (OFSP) is one of the unique varieties of sweet potatoes tuber that has attracted food professionals due to its great health benefits. This study investigates into ß-carotene and antioxidant properties of OFSP composite bread. Random Surface Methodology was used for the experimental design. Analysis carried out on the bread includes antioxidant activity, alpha-amylase, and alpha-glycosidase inhibitory activity, protein & ß-carotene retention/losses, glycemic index, and sensory evaluation. Total phenol ranged from 7.32 to 21.93 mg GAE/g, total flavonoid ranged between 6.12 and 13.20 mg QE/g and FRAP ranged from 12.31 to 40.36 mg AEE/g. The estimated glycemic index ranged from 51.42% to 72.80%. The value of ß-carotene before and after processing ranged from 15.4 to 39.1 mg/100 g and 8.9 to 18.4 mg/100 g, respectively. OFSP composite bread has high antioxidant potential and may be used as functional foods. PRACTICAL APPLICATIONS: Orange-fleshed sweet potatoes (OFSP) is a novel variety of sweet potatoes that have been sight-saw to owe numerous health benefits in terms of vitamins, minerals, ß-carotene, antioxidants but it is low in protein. Incorporation of plant protein will help to increase its protein content and enhance its utilization in confectionery industries as a good carrier for antioxidants and other health benefits components.

Chemical Compositions and Antioxidant Properties of Orange Fleshed Sweet Potato Leaves and the Consumer Acceptability in Vegetable Soup.

The purpose of this study is to determine the chemical compositions, anti-nutrient compositions, antioxidant properties, and phenolic profile of the leaves of orange fleshed sweet potato varieties [King J (UMUSPO1) and mother's delight (UMUSPO2)] in Nigeria and their suitabilities in soup preparation. Freshly harvested leaves of the two varieties of orange fleshed sweet potato were sorted, cleaned, dried, and milled into powder. The dried leaves were assessed for their chemical compositions viz proximate and mineral compositions, the anti-nutrient compositions, antioxidant properties, and phenolic profile. The overall acceptability of the leafy vegetables in the preparation of a local soup (Edikang Ikong) was evaluated. The ash, fat, and protein contents of UMUSPO1 leaves were higher than UMUSPO2, similarly UMUSPO1 leaves had higher mineral contents. Phytate and saponin contents were higher in UMUSPO2, however, the calculated molar ratios were below critical levels. The 2,2-diphenyl-1-picrylhydrazyl hydrate radical scavenging activity and ferric reducing antioxidant power assay were higher in UMUSPO1. Seven phenolic compounds were identified and quantified in both leaves with gallic acid being the most abundant. The taste of soup prepared with UMUSPO2 was rated higher, however, no significant difference was observed in the overall acceptability of the soups. The two leaves are good sources of nutritional antioxidants and can be suitable for the management of some disease conditions linked to oxidative stress.

HPLC-DAD Phenolic Profiling and In Vitro Antioxidant Activities of Three Prominent Nigerian Spices.

Spices and herbs have antioxidant, anti-inflammatory, and anti-microbial properties, amongst others. These characteristics are attributable to their composition, such as high polyphenol and flavonoid contents that are responsible for their antioxidative properties. Methanolic extracts of Ocimum basilicum (OB), Xylopia aethiopica (XA), and Piper guineensis (PG) were evaluated to profile their phenolic compounds and in vitro antioxidant properties. High performance liquid chromatography with diode-array detection phenolic compounds profiling revealed that quercetin, quercitrin, and isoquercitrin are the most prevalent phenolic compound in OB, XA, and PG, respectively. All the extracts possessed good antioxidant activity. XA showed the highest total phenolic content of 29.50 mg gallic acid equivalents/g, a total flavonoid content of 21.17 mg quercetin equivalents/g, 2,2-diphenyl-1-picrylhydrazyl and 2,2'-azino-bis(3-ethylbenzothiazoline-6-sulphonic acid) radical scavenging abilities of 29% and 88.23%, respectively, and a nitric oxide scavenging activity of 44.13 mg/g. Thus, the XA methanolic extract demonstrated a high content of phenolic compounds and significant antioxidative properties, with prospective potency to prevent oxidative damage and promote better cardiovascular health.

Influence of Sourdough Fermentation on Amino Acids Composition, Phenolic Profile, and Antioxidant Properties of Sorghum Biscuits.

Biscuits were produced from sorghum with and without the addition of sourdough. The influence of sourdough fermentation on the amino acids composition, phenolic profile, and antioxidant properties of the biscuits were evaluated. Phenolic compounds of the biscuits were identified and quantified using gas chromatography/mass spectrometer. The total phenol contents (TPC), total flavonoid contents (TFC), ferric reducing antioxidant properties (FRAP), 2,2'-azinobis( 3-ethylbenzothiazoline-6-sulphonic) (ABTS) scavenging ability, 1,1-diphenyl-2-picryl-hydrazy (DPPH) scavenging ability, and nitric oxide (NO) scavenging ability of the biscuits were determined. Addition of sourdough increased the total essential amino acids, total non essential amino acids, hydrophobic, and aromatic amino acids contents of the biscuits. Essential amino acid index, biological value, and predicted protein efficiency were higher in biscuits with sourdough than in biscuits without sourdough. Six phenolic compounds were identified and quantified in the biscuits. Ferulic acid was the most prominent phenolic compound, followed by chlorogenic acid. TPC, TFC, FRAP, ABTS, DPPH, and NO scavenging abilities increased significantly with the addition of sourdough. Sorghum biscuits with sourdough could be useful in dietary interventions to prevent protein-energy malnutrition. Similarly, the presence of bioactive phenolic compounds and their antioxidant efficacy suggest health benefits in the management of oxidative stress and degenerative diseases.

Development of value-added nutritious crackers with high antidiabetic properties from blends of Acha (Digitaria exilis) and blanched Pigeon pea (Cajanus cajan).

Pigeon pea was treated by blanching and used to supplement acha flour for the development of functional cracker biscuits. The flour ratios for acha and pigeon pea were 100:0 (ACC), 80:20 (APC1), and 70:30 (APC2), respectively. The developed cracker biscuits were evaluated for chemical acid compositions, antioxidant, as well as antidiabetic properties. Protein contents of the formulated crackers increased with increase in supplementation with pigeon pea flour. The antinutrient content of the formulated snack was low hence may not adversely affect nutrient bioavailability. Glutamic and aspartic acids were the predominant amino acids while methionine and lysine significantly increased as a result of supplementation with pigeon pea flour. The biscuit exhibited good antioxidant properties indicated by its strong ability to scavenge hydroxyl, superoxide, DPPH radicals, and reduced Fe3+ to Fe2+. The formulated snack especially APC2 possessed low glycemic index (47.95%) and significantly inhibited the key digestive enzymes (α-amylase and α-glucosidase). All parameters evaluated indicated that APC2 could serve as a functional snack in the management of hyperglycemia (diabetes) and prevention of associated degenerative diseases.

Multiresponse Optimization and Prediction of Antioxidant Properties of Aqueous Ginger Extract.

The influence of extraction temperature, powder concentration, and extraction time on the antioxidant properties of aqueous ginger extract was investigated. The possibility of estimating the antioxidant properties of the extract from its absorbance and colour properties was also investigated. Results indicated that powder concentration was the most significant factor to consider in optimizing antioxidant extraction. However, temperature and time still influenced the 2,2'-azinobis-(3-ethylbenzothiazoline-6-sulfonic acid) (ABTS) radical scavenging activity while extraction temperature influenced the 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical scavenging activity of the extract. Using the total phenol content, total flavonoid content, ABTS radical scavenging activity, and DPPH radical scavenging activity of the extract, the multiresponse optimization condition for extraction of antioxidant based on the experimental range studied is 96°C, 2.10 g/100 mL, and 90 min. The absorbance of the ginger extract at 610 nm could be exploited for rapid estimation of its total flavonoid and polyphenol with a R2 of 0.713 and 0.753, respectively.

Optimization and prediction of antioxidant properties of a tea-ginger extract.

A response surface approach was used to investigate the effects of temperature, concentration, and time on the antioxidant properties (total flavonoid (TF), total phenol (TP), peroxide scavenging activity (PS), iron chelating activity (IC), DPPH radical-scavenging ability (DPPH), ABTS assay (ABTS)) of aqueous extract of tea-ginger (2:1) powder. Color indices, pH, and redox potential of the tea-ginger powder were also measured and used as independent variables for the prediction of antioxidant properties of the extract using ordinary least square (OLSR), principal component (PCR), and partial least square (PLSR) regression. The R (2) values for TP, TF, ABTS, and PS response surface models were 0.8873, 0.9639, 0.6485, and 0.5721, respectively. The OLSR, PCR, and PLSR were able to provide predictive models for DPPH, TP, and TF of the tea-ginger extract (P < 0.05). The PLSR gave the most parsimonious model with an R (2) of 0.851, 0.736, and 0.905 for DPPH, TP, and TF, respectively.

HPLC-DAD Phenolic Characterization and Antioxidant Activities of Ripe and Unripe Sweet Orange Peels.

Phenolic compounds of unripe and ripe sweet orange peels were determined using a high-performance liquid chromatography separation method with diode array detector (HPLC-DAD). The in vitro antioxidant properties and the EC50 (concentration required to obtain a 50% antioxidant effect) values were also determined. The predominant phenolic compounds were quercitrin, rutin, and quercetin with values of 18.77 ± 0.01 mg/mL, 18.65 ± 0.03 mg/mL, and 10.39 ± 0.01 mg/mL respectively in unripe orange peel and 22.61 ± 0.01 mg/mL, 17.93 ± 0.03 mg/mL, and 14.03 ± 0.02 mg/mL respectively in ripe orange peel. The antioxidant properties revealed 2,2'-azino-bis(3-ethyl benzothiazoline-6-sulfonic acid) diammonium salt (ABTS) scavenging ability of both unripe and ripe orange peels respectively as 14.68 ± 0.01 and 16.89 ± 0.02 mmol TEAC/g, the Ferric Reducing Antioxidant Properties (FRAP) as 70.69 ± 0.01 and 91.38 ± 0.01 mg gallic acid equivalents/100g, total phenol content as 5.27 ± 0.03 and 9.40 ± 0.01 mg gallic acid equivalents/g and total flavonoid content as 3.30 ± 0.30 and 4.20 ± 0.02 mg quercetin equivalent/g. The antioxidant assays showed enhanced potency of extract from ripe orange peel with EC50 values of 2.71 ± 0.03 mg/mL for 2,2-diphenyl-1-picrylhydrazyl (DPPH), 0.67 ± 0.03 mg/mL for hydroxyl radicals (OH*), 0.57 ± 0.02 mg/mL for Fe(2+) chelation, and 0.63 ± 0.06 mg/mL for malondialdehyde (MDA), and was more potent than unripe orange peel.