Search results

1 – 10 of over 1000
To view the access options for this content please click here
Article

Vellingiri Vadivel and Hans Konrad Biesalski

The purpose of this paper is to evaluate the antioxidant and type II diabetes related enzyme inhibition properties of phenolic extract from raw and traditionally processed…

Abstract

Purpose

The purpose of this paper is to evaluate the antioxidant and type II diabetes related enzyme inhibition properties of phenolic extract from raw and traditionally processed Indian under‐utilized food legume grains, Bauhinia purpurea L. (purple camel's foot seeds).

Design/methodology/approach

The methanolic extract was prepared from the raw and traditionally processed seed samples and analyzed for total phenolic content. The antioxidant activity and type II diabetes related enzyme inhibition properties of methanolic extract and their relationship with phenolic content was demonstrated.

Findings

The methanolic extract of raw seed materials contained total free phenolic content of 14.45±1.62 g catechin equivalent/100 g extract DM. Encouraging levels of ferric reducing/antioxidant power (FRAP, 1203 mmol Fe[II]/mg extract), inhibition of ß‐carotene degradation (45.37 percent) and scavenging activity against DPPH (63.60 percent) and superoxide (42.14 percent) radicals were exhibited by the raw samples. Further, it also recorded 80.69 percent of α‐amylase and 63.74 percent of α‐glucosidase enzyme inhibition characteristics under in vitro starch digestion bioassay. Sprouting+oil‐frying caused an apparent increase on the total free phenolic content, antioxidant and free radical scavenging capacity, while soaking+cooking as well as open‐pan roasting treatments show diminishing effects.

Originality/value

Identification of suitable processing technique offered a good strategy to improve the phenolic content and health relevant functionality of B. purpurea seeds, which could be envisaged as a dietary ingredient in the formulation of supplementary foods with therapeutic value to manage type II diabetic patients.

To view the access options for this content please click here
Article

Melek Çol Ayvaz, Figen Aksu and Filiz Kır

Mushrooms have always been treasured and appreciated, thanks to their nutritional as well as medicinal properties. The purpose of this paper is to reveal these properties…

Abstract

Purpose

Mushrooms have always been treasured and appreciated, thanks to their nutritional as well as medicinal properties. The purpose of this paper is to reveal these properties such as antioxidant activities and enzyme inhibition potentials of three mushroom species from Ordu, Turkey. Furthermore, phenolic profiles which are believed to be source of these properties are investigated.

Design/methodology/approach

The assays followed to determine total phenolic, flavonoid and antioxidant contents, antioxidative and enzyme inhibition activities are spectrophotometric methods. Phenolic profiles of mushroom samples were investigated by using the HPLC system.

Findings

The highest phenolic content was found for Lactarius deliciosus. Pyrogallol was the major phenolics in all three samples. Total phenolic content values supported that finding. But, total flavonoid content was the maximum for Cantharellus cibarius. The magnitude of the antioxidant activities revealed by the different tests varied between species. Furthermore, inhibition potential degrees on acetylcholinesterase, butrylcholinesterase, tyrosinase and urease activities were worth mentioning. Lactarius pyrogalus had anti-tyrosinase activity with a 26.229 percent inhibition rate. IC50 values for urease inhibition effect of mushroom samples were in the range of 0.37–0.90 mg/mL.

Originality/value

Enzyme inhibitory potentials for L. pyrogalus was revealed first time. On the other hand, studies on anti-tyrosinase activity of mushrooms are very rare, while almost no studies have been conducted on anti-urease activity. So, the results of present study are very valuable. Thus, the obtained data not only increase the ecological importance of the region but also provide significant contributions to the literature in terms of new sources rich in antioxidants.

Details

British Food Journal, vol. 121 no. 6
Type: Research Article
ISSN: 0007-070X

Keywords

To view the access options for this content please click here
Article

Vania Silva Carvalho and Ana Carolina Conti-Silva

This paper aims to examine the bioactive compounds and texture properties of cereal bars formulated with banana peel flour during storage.

Abstract

Purpose

This paper aims to examine the bioactive compounds and texture properties of cereal bars formulated with banana peel flour during storage.

Design/methodology/approach

Seven cereal bars were produced and stored during 11 months, under vacuum and protected from the light. The total phenolic compounds, the activity antioxidant by ABTS [2,2′-Azino-bis(3-ethylbenzothiazoline-6-sulfonic acid)] method, the DPPH (2,2-diphenyl-1-picryl-hydrazyl-hydrate) method expressed as EC50 (concentration required to reduce the original amount of free radicals by 50 per cent) and texture properties were evaluated over the storage period.

Findings

In general, total phenolic compounds decreased during storage (from 4.19 to 1.11 mg GAE. g-1f.w.). Although the total antioxidant activity (ABTS method) increased during the fifth month, it reduced during storage (from 3.41 to 0.30 µmol TE.g-1f.w.); and the EC50 was not modified in many formulations, though it decreased in other formulations during storage period (from 3913 to 19221 g fruit.g-1 DPPH). The force of rupture began to increase in the fourth month (reaching 62.4 N), and hardness began to increase in the ninth month (reaching 444 N). The formulation and time factors influenced the total phenolic compounds, total antioxidant activity (ABTS method), force of rupture and hardness, while EC50 was only influenced by the formulation (p-value = 0.001). A principal component analysis showed that time had little effect on the most important characteristics considered in description of the cereal bars.

Originality/value

Cereal bars can be consumed up to the third month of storage, considering the texture of the products. Moreover, the presence of bioactive compounds in cereal bars depends on the addition of banana peel flour, which it contributes to the insertion of total phenolic compounds and total antioxidant activity in cereal bars, aggregating functional properties in these products.

Details

Nutrition & Food Science, vol. 48 no. 3
Type: Research Article
ISSN: 0034-6659

Keywords

To view the access options for this content please click here

Abstract

Purpose

Bambara groundnut is a hard-to-cook grain and this has limited its utilisation to some extent. However, the grain is a good source of phytochemicals with antioxidant properties. This study investigated the total phenol content, antioxidant, anti-inflammatory and anti-microbial potentials of hot-water extract of four Bambara groundnuts differentiated by their seed coats (cream, black, maroon and brown).

Design/methodology/approach

Bambara grains were heated in water at a ratio 1:20 (w/v) and the grains brought to boiling in a controlled water bath. As soon as boiling started, the temperature was reduced to 90 °C to reduce the evaporation rate. The extracts were withdrawn within 30 min, which was chosen from a preliminary study where beyond this time, the extract was drying off and the amount of solution obtained was not sufficient for the initial run. Grain colour and composition and antioxidant, antimicrobial and anti-inflammatory properties of the extract were determined using standard methods.

Findings

Protein (20.57–26.31%) and carbohydrate (55.43–61.09%) were the major components of the grain. Grain type and boiling time generally affected the total phenolic content of the extract. Cream Bambara displayed substantially lower total phenolic content at all boiling times compared with the maroon, brown and black Bambara groundnuts. The total flavonoid contents and total phenolic contents of the Bambara groundnut extracts were dependent on the boiling time and type of grain. The extracts showed no activity against Candida albicans, but the maroon coat Bambara demonstrated a peak inhibition of 6.00 mm against Escherichia coli. The total phenolic, flavonoid contents and the antioxidant properties of the grains generally followed the order Maroon > Black > Brown.

Originality/value

This study has demonstrated the possibility of promoting the use of Bambara groundnut beyond the current level of usage by using simple processing method of boiling to extract phytochemicals with medicinal properties.

Details

British Food Journal, vol. ahead-of-print no. ahead-of-print
Type: Research Article
ISSN: 0007-070X

Keywords

To view the access options for this content please click here
Article

S. O. Salawu, O. F. Alao, O. F. Faloye, A. A. Akindahunsi, A. A. Boligon and M. L. Athayde

The purpose of this paper is to focus on the antioxidant properties of two phenolic-rich varieties of Nigerian local rice and their anti-cholinesterase potential after in

Abstract

Purpose

The purpose of this paper is to focus on the antioxidant properties of two phenolic-rich varieties of Nigerian local rice and their anti-cholinesterase potential after in vitro-simulated gastrointestinal digestion, with the aim of establishing their actual antioxidant and nutraceutical potential after their passage through the gastrointestinal tract upon consumption.

Design/methodology/approach

Two local rice varieties, commonly referred to as “Gboko” and “Ofada” rice commonly grown in Benue State, a middle belt region of Nigeria and south western regions of Nigeria, respectively, were locally processed. Each of the processed grains were divided into two portions; one portion was left uncooked, while the second portion was boiled conventionally as eaten, dried and subsequently milled into powder. The milled samples of the raw and boiled rice were treated with acidified methanol to obtain the methanol extracts; another portion of each samples was subjected to in vitro enzyme digestion using standard methods to mimic human digestion; and the third portion was treated using the same scheme of in vitro digestion without the sets of enzyme which was used to serve as a control for enzyme treatment. The quali-quantitative phenolic profiles of the two local varieties were carried out with the aid of high-performance liquid chromatography with diode-array detection (HPLC-DAD) method. The antioxidant potential and anti-cholinesterase action of the methanolic extracts, the simulated in vitro digested model and the enzyme-treated controls of the rice samples were determined using standard methods and data obtained were subjected to ANOVA; the differences of means were separated using Duncan’s multiple range test (DMRT).

Findings

The quali-quantitative assessment of phenolic compounds in the two studied local varieties revealed the presence of some phenolic acids and flavonoids, with a decreased level of most of the identified phenolic compounds after boiling. In vitro enzyme-digested rice for both raw and boiled rice samples showed significantly higher total phenolic content, total flavonoid content, ferric-reducing antioxidant power, 2, 2′-azino-bis-3-ethylbenzothiazoline-6-sulphonic acid (ABTS+) scavenging and NO− inhibitory activities than the aqueous-methanolic extracts and the enzyme-treated controls. The aqueous-methanolic extracts displayed a higher 1, 1 diphenyl-2-picrylhdrazyl radical scavenging activity and inhibited Fe2+-induced lipid oxidation in rat’s brain and liver homogenate than that displayed by the in vitro enzyme-digested samples. In vitro enzyme-digested and boiled “Gboko” and “Ofada” rice and raw “Ofada” rice have the potential of inhibiting acetylcholine esterase (AChE) activity. While methanolic extracts of raw and boiled “Ofada” and “Gboko” rice exhibited the potential to inhibit butrylcholinesterase activity. The result of this paper indicates that the selected rice varieties possess antioxidant capacities which are better released after the simulated in vitro enzyme digestion; the result also showed the anti-cholinesterase potential of the studied rice grains and, therefore, they can be considered as nutraceutical health supplements.

Originality/value

The paper has demonstrated the antioxidant potentials of the phenolic-containing two Nigerian local rice varieties and established their anti-cholinesterase potential after simulated in vitro enzyme digestion.

Details

Nutrition & Food Science, vol. 46 no. 2
Type: Research Article
ISSN: 0034-6659

Keywords

To view the access options for this content please click here
Article

Pin‐Rou Lee, Rou‐Ming Tan, Bin Yu, Philip Curran and Shao‐Quan Liu

The purpose of this study was to characterise the physiochemical properties of selected exotic seasonal tropical fruits available in Singapore.

Abstract

Purpose

The purpose of this study was to characterise the physiochemical properties of selected exotic seasonal tropical fruits available in Singapore.

Design/methodology/approach

A total of 11 seasonal tropical fruits including cempedak, chiku, custard apple, jackfruit, longkong, mangosteen, red jambu, pearl jambu, rambutan, salak and starfruit were analyzed for their sugars, organic acids and free phenolic acids composition using liquid chromatographic methods. Total phenolic content (free and bound), total soluble solids and pH were determined using Folin‐Ciocalteu method, refractometer and pH meter, respectively.

Findings

Fructose, glucose and sucrose were the main sugars in all the fruits. Cempedak had the highest sucrose concentration, while custard apple had the highest content of fructose and glucose. Malic and citric acids were the major organic acids in most of the fruits, except for pearl jambu and red jambu where succinic acid was the dominant acid. The total phenolic content varied from 122.94 to 712.20 mg gallic acid equivalent (GAE)/kg fresh weight (FW). Ferulic (0.631 mg/kg) and sinapic acids (1.506 mg/kg) were the predominant free phenolic acids in custard apple, while caffeic acid was the main free phenolic acid in jackfruit, salak and starfruit.

Originality/value

The paper demonstrates that the physiochemical characteristics of the 11 tropical fruits varied markedly, which is responsible for the differential flavour and stability. The findings are useful for epidemiological research and predicting the degree of ripeness, stability and post‐harvest processing required for these fruits.

Details

Nutrition & Food Science, vol. 43 no. 3
Type: Research Article
ISSN: 0034-6659

Keywords

To view the access options for this content please click here
Article

Sitti Aralas, Maryati Mohamed and Mohd Fadzelly Abu Bakar

Salak (Salacca zalacca) is a species of palm tree native to Malaysia and Indonesia. The fruit is also known as “snake fruit” due to its reddish‐brown scaly skin. Four…

Abstract

Purpose

Salak (Salacca zalacca) is a species of palm tree native to Malaysia and Indonesia. The fruit is also known as “snake fruit” due to its reddish‐brown scaly skin. Four different varieties of the fruits (i.e. SS1, SS2, SS3 and SS4) have been established by Sabah State Agriculture Department, Malaysia. The purpose of this paper is to investigate and compare the antioxidant properties and phytochemicals content in the edible portion of the fruits.

Design/methodology/approach

Four different varieties of the fruits were collected and analysed for the antioxidant properties (2,2‐diphenyl‐1‐picrylhydrazyl (DPPH) and ferric reducing/antioxidant power (FRAP) assay), total phenolic and total flavonoid contents using spectrophotometry analysis. Ascorbic acid was determined using titration method.

Findings

The results showed the total phenolic and flavonoid contents of the samples were in the range of 12.6‐15.0 mg gallic acid equivalent/g and 4.9‐7.1 mg catechin equivalent/g of dry sample, respectively. The antioxidant activities of the extracts (using DPPH assay) were highly correlated with total phenolic and moderately correlated with flavonoid content. The reducing capabilities of the extracts using FRAP assay were moderately correlated with all phytochemicals tested. The results suggested that the phytochemicals and antioxidant activity of salak is mildly affected by variety. The high phytochemicals and antioxidant properties of S. zalacca indicated that the fruit possessed potential health benefits properties.

Originality/value

Salak fruit is now being developed into fruit juice, pickle and other food products. The commercialization of the fruit may be enhanced if more knowledge on its potential health benefits is studied and discovered. The economic and nutraceutical values might increase and will contribute greatly to the local people.

Details

Nutrition & Food Science, vol. 39 no. 3
Type: Research Article
ISSN: 0034-6659

Keywords

To view the access options for this content please click here
Article

Dalamu, Charanjit Kaur, Meenakshi Singh, Shweta Walia, Subodh Joshi and A.D. Munshi

The purpose of this paper is to provide a comprehensive evaluation of 34 onion genotypes for their antioxidant activity (AOX) content of phenolics, quercetin and pungency…

Abstract

Purpose

The purpose of this paper is to provide a comprehensive evaluation of 34 onion genotypes for their antioxidant activity (AOX) content of phenolics, quercetin and pungency to enable selection of the best genotype for later experiments of variety breeding or to be used as a vector in the improvement of well‐established traditional genotype.

Design/methodology/approach

A comprehensive screening of 34 onion (red, pink and white) genotypes is carried out in order to determine the variation in phenolics, quercetin and total AOX as potential for breeding for their enhanced levels.

Findings

The AOX in red genotype with highest levels of phenolics is roughly three times higher than commercial white genotype. Pungency levels range from 3.12 to 10.48  μmoles pyruvic acid/g. Mean phenolic and quercetin content ranges from 60.1 to 1094.8 mg gallic acid equivalents/kg and 22.0 to 890.5 mg/kg quercetin, respectively. AOX in red genotype (expressed as μmoles trolox/g) ranges from 1.97 to 5.45 and 3.60 to 6.61 in ferric reducing antioxidant power and cupric ion reducing capacity assays, respectively. Selections, Sel‐383, Sel‐397, Sel‐61‐383, and Inbreds, I‐40, I‐80 and Burgundy are potential genotype with high pungency and AOX.

Research limitations/implications

An improvement in breeding effort designed to increase the phenolics, quercetin and total AOX in onions (Allium cepa L.) provides selected material for analysis. Onion genotype and breeding lines with improved AOX are identified that would help breeders produce onions high in health promoting compounds.

Originality/value

The paper attempts to examine onion genotypes using standardized in‐vitro AOX assays.

Details

Nutrition & Food Science, vol. 40 no. 1
Type: Research Article
ISSN: 0034-6659

Keywords

To view the access options for this content please click here
Article

Vinti Singh, Jyotsana Singh, Radha Kushwaha, Monika Singh, Sandeep Kumar and Awadhesh Kumar Rai

Flowers and fruits of Madhuca longifolia (Koenig) (mahua) tree are edible and used as traditional Indian medicines. The physicochemical properties of different parts of…

Abstract

Purpose

Flowers and fruits of Madhuca longifolia (Koenig) (mahua) tree are edible and used as traditional Indian medicines. The physicochemical properties of different parts of mahua are investigated. This study aims to estimate the different mineral contents, polyphenols compounds and antioxidant activities by 2,2-diphenyl-1-picrylhydrazyl inhibition, reducing power, free radical scavenging activity using 2,2'-azino-bis (3-ethylbenzothiazoline-6-sulfonic acid) and ferric reducing antioxidant power assays of mahua flower, ripe and unripe fruit.

Design/methodology/approach

Flavonoids were identified and quantified in yellow flowers and fruits of M. longifolia tree by high-performance liquid chromatography with diode array detector. Low molecular weight carbohydrates were determined by the ICBio scan, a specific method for determining of carbohydrates. Mineral content is determined by laser-induced breakdown spectroscopy (LIBS) and atomic absorption spectroscopy. Physicochemical, nutritional and mineral properties of mahua flower, ripe and unripe fruit were investigated by the statistical approach of principal component analysis (PCA).

Findings

Ascorbic acid, gallic acid (GA), quercetin and myrcetin were the phenolic compounds identified and quantified in mahua flower and fruit extracts. Sugar profiling of mahua flowers and fruits confirmed the presence of inositol, sorbitol, mannitol, dextrose, fructose, sucrose, raffinose and maltose. The mineral content of Na, K, Mg and Ca was present in quite a good amount in all samples. Total phenolic content (TPC) was significantly high in mahua flower (25.3 ± 1.0 mg GA equivalent/g FW) followed by mahua unripe (15.8 ± 1.0 mg GA equivalent/g FW) and ripe fruit (14.3 ± 1.0 mg GA equivalent/g FW) at p = 5%. In contrast, total flavonoid contents (TFCs) were highest in ripe fruit, then mahua flower and unripe fruit. Positive correlations were predicted by PCA for mahua flower with TPC, antioxidant activity assays and minerals except for Na; ripe fruit with TFC and Na; and unripe fruit with maltose and sorbitol.

Originality/value

This study demonstrates the application of LIBS for the determination of elements present in the mahua flowers and fruits and reveals that mahua can be a good source of nutrients. Sugar profiling of mahua flower showed that it is a rich source of reducing and non-reducing sugar, proving that mahua flower juice can be used as a natural sweetener in the development of different food products, namely, biscuits, cookies, cake, jam, jelly, juice and squash.

Details

Nutrition & Food Science , vol. 51 no. 2
Type: Research Article
ISSN: 0034-6659

Keywords

To view the access options for this content please click here
Article

Pei Yun Wong and Seok Tyug Tan

Literature has consistently reported that coloured plants are rich in dietary bioactive compounds. Therefore, this study aims to compare the total phenolic content and…

Abstract

Purpose

Literature has consistently reported that coloured plants are rich in dietary bioactive compounds. Therefore, this study aims to compare the total phenolic content and antioxidant activities in selected coloured plants (blue butterfly pea flower, roselle calyx, yellow bell pepper and purple sweet potato).

Design/methodology/approach

Total Phenolic Content (TPC) was determined using Folin–Ciocalteu assay, while antioxidant activities were evaluated using 2,2-dophenyl-1-picryl-hydrazyl-hydrate (DPPH) radical scavenging, Ferric Reducing Antioxidant Power (FRAP) and Trolox Equivalent Antioxidant Capacity (TEAC) assays.

Findings

TPC was reported from 273.15 ± 19.57 µg GAE/g DW (blue butterfly pea flower extract) to 363.10 ± 7.94 µg GAE/g DW (roselle calyx extract). Antioxidant activities as determined by DPPH assay ranged from 17.26 ± 0.06% (purple sweet potato extract) to 83.38 ± 1.04% (yellow bell pepper extract); while for FRAP assay was 4.92 ± 0.18 mg Fe (II)/g DW (purple sweet potato extract) to 128.33 ± 11.59 mg Fe (II)/g DW (roselle calyx extract). On the other hand, TEAC values were in the range of 15.26 ± 2.83 µg Trolox/g DW (roselle calyx extract) to 364.27 ± 7.14 µg Trolox/g DW (blue butterfly pea flower extract). A significant moderate positive correlation was observed between TPC and DPPH (r = 0.562) as well as TPC and FRAP (r = 0.686).

Originality/value

This study was the first to compare the total phenolic content and antioxidant activities in coloured plants. Findings derived from this study can be extended to the formulation of natural food colourants and nutraceuticals.

Details

British Food Journal, vol. 122 no. 10
Type: Research Article
ISSN: 0007-070X

Keywords

1 – 10 of over 1000