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Article
Publication date: 7 September 2010

Randall Arce Alvarado and Anita R. Linnemann

The purpose of this paper is to analyze whether consumers can discriminate coffees in the same way as a professional coffee judge, a cupper, to assess the relevance of…

1192

Abstract

Purpose

The purpose of this paper is to analyze whether consumers can discriminate coffees in the same way as a professional coffee judge, a cupper, to assess the relevance of cuppers' evaluations for taste differences perceived by consumers.

Design/methodology/approach

In total, 23 samples sold in international stores as Tarrazú coffee were bought. A cupper evaluated these samples using the international cupping procedures for the quality attributes aroma, fragrance, body and acidity. Of the 23 samples, five were used in a triangle test carried out by a panel of 12 non‐expert consumers to determine if their discriminations matched the expert's judgment.

Findings

Results from the cupper gave a high variability of the coffees evaluated. The results of the consumer panel demonstrated that discrimination between coffees by consumers was predicted by acidity differences assessed by the cupper. The same held for body but not necessarily for fragrance and aroma.

Originality/value

The paper revealed that discrimination between the coffees by the consumer panel matched the coffee cupper's evaluation differences. The high consistency of the results obtained from the consumer panel underpins that the respondents did not have much difficulty in rating the coffees with the same scores as the professional coffee judge. Thus, differences in coffee quality, notably with respect to acidity, are important to consider in coffee production and marketing as consumers can perceive them and thus use this information when deciding whether or not to buy the product again.

Details

British Food Journal, vol. 112 no. 9
Type: Research Article
ISSN: 0007-070X

Keywords

Article
Publication date: 26 October 2018

Safa Abd El kader Mohamed Hamed and Rushdya Rabee Ali Hassan

This paper aims to investigate the effect of acidity on the morphology of archeological paper, especially in the presence of colors and whether natural pigments play a…

Abstract

Purpose

This paper aims to investigate the effect of acidity on the morphology of archeological paper, especially in the presence of colors and whether natural pigments play a role in the process of degradation.

Design/methodology/approach

The morphological changes in the cellulosic fibers of the manuscripts because of acidity were investigated using environmental scanning electron microscope (ESEM). Ten historical samples were collected from different manuscripts suffering from acidity. X-ray diffraction was used to identify the inks and pigments that were used in some samples. Additionally, Fourier transform infrared microscopy was used to identify the binding medium.

Findings

The results confirmed that carbon ink, ultramarine, cinnabar and gold pigments were applied to some manuscripts with Arabic gum. As for ESEM investigation, the results proved that acidity badly affected the integrity of the cellulosic fibers resulting in their embrittlement. The micrographs showed differences in fiber degradation according to pH value. The presence of inks and pigments increased the degradation extent resulting from acidity.

Originality/value

This paper addresses a specific need to study the behavior of degradation in paper manuscripts, thus helping the conservators find solutions to the phenomenon.

Details

Pigment & Resin Technology, vol. 48 no. 2
Type: Research Article
ISSN: 0369-9420

Keywords

Article
Publication date: 18 March 2022

Daniel Obregon Valencia and María R. Sun Kou

The goal of this paper is to model the activated carbon adsorption capacity of cadmium using a polynomial regression model. The properties that influence the removal of…

25

Abstract

Purpose

The goal of this paper is to model the activated carbon adsorption capacity of cadmium using a polynomial regression model. The properties that influence the removal of heavy metals by activated carbon must be taken into consideration in order to synthesize materials specific to the characteristics of the pollutant.

Design/methodology/approach

Multivariable analysis applications allow a comprehensive description of the relationship between activated carbon surface properties and heavy metal adsorption.

Findings

The authors use a second-grade polynomial regression model to determine the influence of porosity and surface acidity in cadmium adsorption by activated carbon.

Originality/value

The authors propose a statistic analysis to correlate the carbon properties with its cadmium adsorption capacity. Model coefficient analysis will give a better comprehension of the influence of activated carbon porosity and surface acidity of cadmium removal.

Details

Multidiscipline Modeling in Materials and Structures, vol. 18 no. 2
Type: Research Article
ISSN: 1573-6105

Keywords

Article
Publication date: 1 December 2005

Rezvan Pourahmad and Mahnaz Mazaheri Assadi

Yoghurt consists of approximately 60 per cent of per capita dairy consumption of Iranian people. Iranian dairy factories use commercial starters which are expensive in…

Abstract

Purpose

Yoghurt consists of approximately 60 per cent of per capita dairy consumption of Iranian people. Iranian dairy factories use commercial starters which are expensive in yoghurt production. Moreover, yoghurt produced by these starters does not completely meet the taste of Iranian consumers. The aims of this study are to produce well qualified yoghurt from isolated native starters and to evaluate microbial, chemical and organoleptic characteristics of products.

Design/methodology/approach

The microflora of Iranian native yoghurts were isolated, purified and identified. The isolated strains were used as starter for the production of yoghurts. Sensory evaluation and measurement of pH, acidity and acetaldehyde content of the samples were carried out. Acidity, pH, acetaldehyde content, and microbial population of the best samples were measured during 21 days of cold storage. SPSS software was used for statistical analysis.

Findings

During the above mentioned storage period, acidity and acetaldehyde content increased significantly (p < 0.05). Significant decreases (p < 0.05) were observed in pH and microbial population. No significant difference in organoleptic characteristics (taste, smell and texture) were found after 21 days of cold storage.

Originality/value

Yoghurt production by native starter cultures instead of commercial ones is beneficial in respect of both economic and organoleptic aspects. The results indicate that the use of isolated native yoghurt starters in manufacturing yoghurt can be satisfactory and can also be extended to the production of yoghurt on an industrial scale.

Details

Nutrition & Food Science, vol. 35 no. 6
Type: Research Article
ISSN: 0034-6659

Keywords

Article
Publication date: 1 July 1982

D. Barišin and C. Jelačič

Summary It has been noticed that during electrolysis of zinc from sulphate solutions in the presence of Germanium, the utilisation of current varies with the change of…

Abstract

Summary It has been noticed that during electrolysis of zinc from sulphate solutions in the presence of Germanium, the utilisation of current varies with the change of concentration of Ge in the electrolyte, and from the neutral electrolyte it decreases with the increase of current which passed through the electrolyte. Therefore dependencies of current utilisation on concentration of acid and concentration of Ge in the electrolyte have been investigated. It has been found the current utilisation decreases when the acidity increases, the decrease being also proportional to the increase of concentration of Ge. The activity of Ge is the more intensive with the higher the acidity. The cause of the fact that concentration of Ge in the electrolyte remains constant after a certain duration of electrolysis has been explained, as well as that the absolute value of this concentration depends only on the initial concentration of Ge. It has been stated that deposition of Ge on the cathode ceases (either in the form of metal or hydride) when the electrolyte has reached an acidity value of about 120 g/l H2SO4.

Details

Anti-Corrosion Methods and Materials, vol. 29 no. 7
Type: Research Article
ISSN: 0003-5599

Article
Publication date: 1 May 2006

B.I.O. Ade‐Omowaye, S.A. Olaniyan, I.A. Adeyemi and O.O. Isola

This paper sets out to focus on the utilization of the locally available raw material to develop an acceptable and high quality non‐alcoholic beverage in Nigeria.

1042

Abstract

Purpose

This paper sets out to focus on the utilization of the locally available raw material to develop an acceptable and high quality non‐alcoholic beverage in Nigeria.

Design/methodology/approach

Maize‐based non‐alcoholic beverages were produced from either plain maize powder or combinations of maize powder and mango or soybean flour. Plain and fruit or soy‐ fortified maize powders were analyzed using standard methods for chemical composition, while total solid, sediment height, pH, titratable acidity, storage stability and microbial load were determined on the formulated beverage products. Taste panel evaluation was conducted to evaluate the acceptability of the products.

Findings

While the protein, fat and ash contents of plain maize powder were 5.69, 5.95 and 0.35 per cent respectively, there was minimal enhancement with fruit addition. However, with 10 per cent soybean addition significant improvement over the unfortified sample in protein (14.62 per cent), fat (10.64 per cent) and ash (0.96 per cent) was obtained. Sediment height was found to be higher for beverage with sour water and least for soy‐fortified beverage. Titratable acidity of beverage samples was found to be 0.022, 0.018, 0.054 and 0.306 per cent (per cent lactic acid) for plain, fruit‐flavoured, soy‐fortified and soured beverages respectively. Variation in titratable acidity was observed depending on the product and storage condition. Sensory evaluation result for beverage prepared with sour water (0–100 per cent) revealed preference for soured beverage with 80 per cent sour water. Also, fruit‐flavoured sample ranked highest in preference followed closely by the plain beverage, while soy‐fortified sample was the least acceptable.

Originality/value

The paper has demonstrated the feasibility of developing acceptable beverage samples from sour water (a by‐product of Ogi usually regarded as waste) and combinations of either maize powder and mango or soybean flour.

Details

Nutrition & Food Science, vol. 36 no. 3
Type: Research Article
ISSN: 0034-6659

Keywords

Article
Publication date: 1 March 1962

J.J. FREWING

The principles of acidity and basicity measurement are explained by describing colour‐indicator titration of aqueous solutions. Similar methods are used to determine…

Abstract

The principles of acidity and basicity measurement are explained by describing colour‐indicator titration of aqueous solutions. Similar methods are used to determine neutralisation values of non‐aqueous solutions such as petroleum products, although electrometric titration is more suitable for dark‐coloured oils and used oils. The practical importance of neutralisation value tests is discussed, with particular reference to additive oils, turbine oils, gear lubricants and transformer oils.

Details

Industrial Lubrication and Tribology, vol. 14 no. 3
Type: Research Article
ISSN: 0036-8792

Article
Publication date: 4 December 2019

Ivan Muzira Mukisa, Stellah Byakika, Rehema Meeme, Alex Paul Wacoo, Wilbert Sybesma and Remco Kort

Traditional fermented products can be adopted as probiotic carriers. This study was aimed at evaluating the potential of using Obushera, a traditional sorghum beverage…

Abstract

Purpose

Traditional fermented products can be adopted as probiotic carriers. This study was aimed at evaluating the potential of using Obushera, a traditional sorghum beverage from Uganda, as a carrier for Lactobacillus rhamnosus yoba.

Design/methodology/approach

Probiotic Obushera was produced by fermenting sorghum malt with Lb. rhamnosus yoba 2012 and Streptococcus thermophilus C106 at 30 °C and at room temperature (21°C-25 °C) for 24 h. Acidity, pH, total soluble solids and microbial counts were monitored. Consumer acceptability and purchase index of probiotic Obushera were compared to four commercial non-probiotic brands. Shelf stability of probiotic Obushera was determined by monitoring changes in pH, acidity, soluble solids, microbial counts and consumer acceptability during refrigerated storage.

Findings

Lactobacillus rhamnosus yoba 2012 multiplied and lowered the pH of Obushera from 5.3 to < 4.0 (p < 0.0001) whilst increasing acidity from 0.21 to 0.46 per cent (p < 0.0001) in 9 h at 30 °C. Consumer acceptability varied with Obushera brand (p < 0.0001). The overall acceptability score of probiotic Obushera (score of 6.4 = like slightly) was similar to that of the two most acceptable commercial brands (scores of 5.8 and 6.6). Acidity, pH and Lb. rhamnosus counts of probiotic Obushera varied within 0.6 per cent –1.05 per cent (p < 0.0001), 3.3–3.4 (p < 0.0001), and 8.2-9.2 log cfu/ml (p < 0.0001), respectively during two months of storage. The overall acceptability of probiotic Obushera (scores of 6.9-7.8) did not change significantly during storage (p = 0.185).

Practical Implications

Traditional fermented foods such as Obushera can be adopted as carriers of probiotic microorganisms.

Originality/value

Use of commercial probiotic strains in traditional fermented foods is a novel approach that can be adopted to improve safety of traditional fermentations and health of consumers.

Details

Nutrition & Food Science , vol. 50 no. 5
Type: Research Article
ISSN: 0034-6659

Keywords

Article
Publication date: 4 January 2022

Shayma T.G. Al-Sahlany and Alaa K. Niamah

The purpose of this study was to assess the bacterial viability, antioxidative activity, antimutagenicity and sensory evaluation of fermented onion types by using…

Abstract

Purpose

The purpose of this study was to assess the bacterial viability, antioxidative activity, antimutagenicity and sensory evaluation of fermented onion types by using probiotic starters after fermentation at 37 °C for 24 hours and storage in the refrigerator for 28 days.

Design/methodology/approach

For onion fermentation, Lactobacillus acidophilus (LA-5), Bifidobacterium bifidum (BB-12), and Streptococcus thermophilus (ST) were utilised. This research was conducted on three types of onion: white onion, red onion and scallion. With a 5% brine solution, the onions were sliced into 3-5 cm long and 1-2 cm wide slices. The process of fermentation was achieved by adding 2% (108 CFU/ gm) of fresh probiotic starter and incubating it for 24 hours at 37 °C. The fermented onion samples were kept in the refrigerator for 28 days. After fermentation and storage, the pH and total acidity were estimated, the vitality of probiotic bacteria was evaluated in samples of the onion species. The Gas chromatography-mass spectrometry (GC-MS) technique was used to identify the bioactive components in fermented onion types. The antioxidant activity of fermented onions was measured using the 2,2-diphenyl-1-picryl-hydrazyl-hydrate (DPPH) radical scavenging activity assay and the hydroxyl radical scavenging activity test. The Ames test was used to detect the antimutagenicity of fermented onion samples.

Findings

After fermentation, the fermented scallion (p = 0.036) has the highest vitality of all the starter bacteria species. The fermentation of onion types produced a pH of between 4.1–4.7 and 0.19–0.23% total acidity, which is in the range of reduced 3.1–3.5 pH values and 0.42–0.63% total acidity after 28 days. The viability of Lactobacillus acidophilus and Bifidobacterium bifidum in fermented scallions was Log. 7.79 and 7.57 CFU/gm. The GC-MS technique found 14 bioactive compounds in fermented white onions and 13 compounds in fermented white onions, with 15 compounds in scallion fermentation. The majority of these bioactive compounds are strong antioxidants. The antioxidant properties of fermented scallion significantly increased after 28 days of storage time, showing an inhibitory effect on the DPPH assay (p = 0.02) and the scavenging activity of the hydroxyl radical assay (p = 0.01). Sensory evaluation tests revealed that the fermented scallion was a suitable product in terms of appearance, aroma and overall acceptability.

Originality/value

Commercially accessible probiotic foods account for a sizable portion of the consumer market. Furthermore, as consumer interest in healthy eating grows, so does demand for plant-based goods. All onion types fermented with probiotic bacteria have many chemical compounds that have both antioxidant and carcinogenic activity. The fermented scallion onion sample was significantly superior to the rest of the other types of onions.

Details

Nutrition & Food Science , vol. 52 no. 6
Type: Research Article
ISSN: 0034-6659

Keywords

Article
Publication date: 5 February 2021

Chin Xuan Tan, Seok Shin Tan, Hasanah Mohd Ghazali and Seok Tyug Tan

Thompson red avocado is a bright red-coloured fruit when ripe. As the global market for avocado fruit is increasing, this unique avocado variety could potentially be the…

Abstract

Purpose

Thompson red avocado is a bright red-coloured fruit when ripe. As the global market for avocado fruit is increasing, this unique avocado variety could potentially be the savory fruit for consumers. The study aimed to evaluate the physicochemical properties of different parts of Thomson red avocado fruit.

Design/methodology/approach

Physical parameters were measured using a calibrated digital balance and a vernier caliper. The methods of the Association of Official Analytical Chemists (AOAC) and a calibrated digital pH meter were used to measure the proximate composition and pH values of different fruit parts. Meanwhile, the total soluble solids and titratable acidity were determined using titration methods.

Findings

Thompson red avocado is a medium-sized fruit with an average mass, length and diameter of 216.92 g, 9.50 and 7.20 cm, respectively. The major part of the fruit is pulp (56.01%), followed by seed (33.04%) and peel (10.94%). Each of these fruit parts was further investigated for their proximate composition, pH, titratable acidity and total soluble solids. All the fruit parts were found to be low in protein (<1%) and titratable acidity (<0.42%), but high in moisture content (>60%). The pH of these fruit parts was in the range of 5.04–5.59. Compared to the peel and seed, the pulp has the highest crude fat (20.79%), but the lowest ash content (1.47%), total carbohydrates (3.39%) and total soluble solids (7.83 ºBrix).

Originality/value

The physical and chemical properties of the commercial avocado varieties such as Fortuna, Collinson, Hass and Barker are well-documented in the literature. Unlike typical avocado fruits, which change from green into dark black, dark green or deep purplish colour when ripe, Thompson red variety changes into red colour when ripe. As the global market for avocado fruit is increasing, the unique, bright-red-coloured Thompson red avocado could potentially be the savoury fruit for consumers. Previous studies reported the nutritional composition of avocado fruit is affected by variety and geographical locations, but the data on the nutritional profile of Thompson red avocado fruit are scarce. Therefore, this study was carried out to determine the physical properties and nutrient contents of Thompson red avocado fruit.

Details

British Food Journal, vol. 124 no. 5
Type: Research Article
ISSN: 0007-070X

Keywords

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