Contents
01.12.2018.
Professional paper
Consumer awareness of the use of food labels in Lagos state, Nigeria
The increase in relative level of education and the growing middle-class income earners in Nigeria have made packaged food items attractive to consumers. These foods provide handy, nutritious and convenient food for consumers; however, they also come with public health concerns. From a policy perspective, food labelling can gauge consumers’ response to the safety conditions of packaged food. However, understanding consumers’ awareness and the use of food label information has attracted little research attention in many developing countries in sub-Saharan Africa. In this study, we investigate consumers’ awareness of the use of food safety labels in Lagos state, Nigeria. We used primary data collected using pretested structured questionnaire from 220 food shoppers who bought pre-packaged foods. A two-stage sampling technique was used to select the respondents. Consumers’ awareness and use of food safety information was revealed using descriptive statistics; Ordinal Regression Analysis was used to examine the socioeconomic factors determining the frequency of reading food safety labels. The study therefore recommends that there should be continuous awareness campaigns on the importance of food labels in ensuring safety and food producers should make sure their food labels are legible.
Samuel T. Danilola, Olubunmi A. Omotesho, Jubril Animashaun
01.12.2018.
Professional paper
Moisture sorption isotherm and thermal characteristics of freeze-dried tuna
Water activity is considered an important factor in assessing the stability of food. Understanding the relationship between water activity and equilibrium moisture content (moisture sorption isotherm) benefits food processing in terms of modeling of drying and estimation of shelf life. In addition, glass transition helps to quantify molecular mobility which helps in determining the stability of food. The aim of this study was to determine the moisture sorption isotherm and thermal characteristics of freeze-dried tuna. These characteristics will help in determining the monolayer moisture and glassy state of the product, at which food is considered most stable. Moisture sorption isotherm at 20°C and thermal characteristics (over a wide temperature range i.e. from -90 to 250 °C) of freeze-dried tuna flesh were measured. Isotherm data were modeled by BET (Brunauer-Emmett-Teller) and GAB (Guggenheim-Anderson–De Boer) models. The GAB and BET monolayer water values were determined as 0.052 and 0.089 g g-1 dry-solids (dry-basis), respectively. In the case of samples at moisture contents above 0.10 g g-1 (wet basis), DSC (Differential Scanning Calorimetry) thermograms showed two-step state changes (i.e. two glass transitions), one exothermic peak (i.e. molecular ordering) and another endothermic peak (i.e. solids-melting). However, the sample at moisture content of 0.046 g g-1 showed three-step state changes (i.e. three glass transitions). The multiple glass transition could be explained by the natural heterogeneity of tuna flesh and inhomogeneity due to molecular incompatibility of the different compositions. The moisture content did not affect the first glass transition temperature nor the exothermic peak (p>0.05), whereas the third glass transition temperature decreased (i.e. plasticized) with increasing moisture content (p<0.05). The solids-melting peak temperature decreased, and enthalpy increased with decreasing moisture content (p<0.05).
Mohammad Shafiur Rahman, Mohammed Khalfan Al-Khusaibi, Kutaila Abbas AL-Farsi, Ismail Mohamed Al-Bulushi, Aisha Abushelaibi, Nasser Al-Habsi
01.12.2018.
Professional paper
Potentials of African nutmeg (Monodora myristica) as a flavourant in cookie production
African nutmeg, a possible local substitute for a commercial food flavourant, remains largely underutilized in Nigeria. Its application potential in cookie production was investigated in this study. African nutmeg (Monodora myristica) seed flour (ANM) was produced using standard method. The flour was substituted for vanilla flavour (VFL) in ratio of 0, 1, 2, 3, and 3.5 g and functional properties of the flour blends (water absorption capacity (WAC), oil absorption capacity (OAC), and bulk density) were determined, using standard methods. Cookies were developed and characterized chemically, physically (colour) and organoleptically using the AOAC method, a colourimeter and sensorypanellistsrespectively. Data were analysed using ANOVA at p<0.05. Replacement of vanilla with African nutmeg had no significant effect on bulk density (0.62g/cm3 – 0.68 g/cm3), but significantly affected WAC (133-142%) and OAC (147-156%) of flour blends. Crude protein (9.44-15.49%), crude fat (3.17-6.50%), total ash (2-2.73%) and crude fibre (0.12-0.23%) contents of the cookie increased, whilst metabolizable energy (385.33-367kcal) decreased. There were reductions in pH (6.83-6.53) and TSS (5.80-1.20). Brown index of the snack increased with addition of nutmeg. Antioxidant indicators (flavonoids, DPPH and phenol) varied among cookie samples. Antinutrients, saponin, tannin and oxalate, were within tolerable limits. All cookie samples were judged acceptable by the panellists, with SLZ being the most acceptable. An acceptable and nutritious snack was produced at 100% replacement. M. myristica seed could serve as substitute for vanilla in the production of cookies and other related snacks.
Kazeem K. Olatoye, Omololo O. Fapojuwo, Joshu A. Olorunshola, Julianah O. Ayorinde
01.12.2017.
Professional paper
Examination of optimum test conditions for a 3-point bending and cutting test to evaluate sound emission of wafer during deformation
The purpose of this study was to investigate optimum test conditions of acoustical-mechanical measurement of wafer analysed by Acoustic Envelope Detector attached to the Texture Analyser. Force-displacement and acoustic signals were simultaneously recorded applying two different methods (3-point bending and cutting test). In order to study acoustical-mechanical behaviour of wafers, the parameters “maximum sound pressure”, “total count peaks” and “mean sound value” were used and optimal test conditions of microphone position and test speed were examined. With a microphone position of 45° angle and 1 cm distance and at a low test speed of 0.5 mm/s wafers of different quality could be distinguished best. The angle of microphone did not have significant effect on acoustic results and the number of peaks of the force and acoustic signal decreased with increasing distance and test speed.
Erdem Carsanba, Gerhard Schleining
01.12.2017.
Professional paper
Extraction and characterisation of cellulose nanocrystals from pineapple peel
The potential of pineapple peel as a source of cellulose nanocrystals was evaluated. Peels skin from fresh-cut fruit was used as raw material. These residues were purified to remove pigments, lipids and hemicellulose, and a bleaching process for delignification was carried out for 4-6 h. All resulting products were characterised for their lignin, hemicellulose, cellulose and ash contents using standard techniques. Dry matter at the end was low (ca. 50%) compared with the raw material (ca. 90%). The process applied resulted in ca. 20% (m/m) of purified cellulose (ca. 80% purity), with ineligible levels of lignin and hemicellulose present, especially when using 6h of bleaching. The purified cellulose was subject to acid hydrolysis for nanocrystal extraction with two testing times, 30 and 60 minutes. These cellulose nanocrystals had small sizes (< 1000 nm), with high variability and negative zeta potential values. The time of extraction did not affect the nanocrystals’ chemical and physical properties. The use of 6 h of bleaching treatment during purification was shown to be more effective than 4 h. Pineapple peel was demonstrated to be a good source of cellulose for the production of cellulose nanocrystals.
Ana Raquel Madureira, Tuğba Atatoprak, Duygu Çabuk, Flávia Sousa, Robert C. Pullar, Manuela Pintado
18.04.2018.
Original scientific paper
Extraction and characterisation of cellulose nanocrystals from pineapple peel
The potential of pineapple peel as a source of cellulose nanocrystals was evaluated. Peels skin from fresh-cut fruit was used as raw material. These residues were purified to remove pigments, lipids and hemicellulose, and a bleaching process for delignification was carried out for 4-6 h. All resulting products were characterised for their lignin, hemicellulose, cellulose and ash contents using standard techniques. Dry matter at the end was low (ca. 50%) compared with the raw material (ca. 90%). The process applied resulted in ca. 20% (m/m) of purified cellulose (ca. 80% purity), with ineligible levels of lignin and hemicellulose present, especially when using 6h of bleaching. The purified cellulose was subject to acid hydrolysis for nanocrystal extraction with two testing times, 30 and 60 minutes. These cellulose nanocrystals had small sizes (< 1000 nm), with high variability and negative zeta potential values. The time of extraction did not affect the nanocrystals’ chemical and physical properties. The use of 6 h of bleaching treatment during purification was shown to be more effective than 4 h. Pineapple peel was demonstrated to be a good source of cellulose for the production of cellulose nanocrystals.
Ana Madureira, Tugba Atatoprak, Duygu Cabuk, Flavia Sousa, Manuela Pintado, Robert C. Pullar
18.04.2018.
Original scientific paper
Fermentation of tender coconut water by probiotic bacteria Bacillus coagulans
Coconut water is currently being considered as an elixir for patients suffering from diseases like dengue and malaria as well as chikungunia to provide hydration properties to the body. It has become a popular beverage for many people owing to its palatability and high mineral content. In this study, the growth, survival and fermentation performance of the probiotic bacterium Bacillus coagulans in coconut water was assessed in order to produce a novel non-dairy, probiotic beverage. The species was characterized on the basis of morphology, physiology and biochemical parameters and its probiotic attributes were assessed. Batch fermentations were carried out for 2 days at a constant 37°C, thereafter the samples were subjected to microbiological and chemical analysis. The results suggested that the specie produced lactic acid and was acid and bile tolerant. The pH and titratable acidity of probiotic fermented coconut water were found to be 4.4 and 0.53 % lactic acid, respectively. The viscosity of fermented coconut water increased significantly from an initial 5.13 mPa.s to 5.35 mPa.s because of the increase in soluble solids content due to exopolysaccharide production by B. coagulans during fermentation. Also, the overall acceptability score of probiotic coconut water was higher than tender coconut water, suggesting its feasibility for use as a probiotic beverage.
Aishwarya Singh Gangwar, Aastha Bhardwaj, Vasudha Sharma
18.04.2018.
Original scientific paper
Energy pattern and conservations of condiment produced from soybean (Glycine max)
Energy being one of the largest operating expenses in most organizations especially manufacturing and processing industries leading to considerable scope for energy conservation and hence cost. Information on energy utilization and conservation pattern were obtained based on time taken, number of person involved and sources of energy using standard energy equations. A total of 445.40 ± 17.32MJkg−1 where thermal energy (420MJ ≈ 94%) and manual energy (25.40MJ ≈ 6%) were the only forms of energy used during production process. Conservation approach I resulted in mean energy of 72.08 ± 1.73MJkg−1 where electrical energy, manual energy and thermal energy accounted for 1.75MJ (3%) 7.34MJ (10%) and 62.99MJ (87%) respectively. Conservation approach II reduced the energy further to 57.24 ± 1.73MJkg−1 as the operation was thermal energy dependent, followed by manual and electrical energy with energy values of 48.13, 7.33 and 1.78MJ equivalent to 84.10%, 12.80% and 3.10% accordingly. Conclusively, traditional method of processing utilized highest energy (445.40MJ) followed by conservation approach I (72.08MJ) and conservation approach II (57.24MJ) was least in energy demand. Conservation approach II permits energy conservation to be 87% as compared with traditional method.
ismaila anjorin, Rahman Akinoso, Mayowa S. Sanusi
18.04.2018.
Original scientific paper
Optimization of osmotic dehydration of chestnut (Castanea sativa Mill.) slices using Response Surface Methodology
Osmotic dehydration of chestnut slices in sucrose was optimized for the first time by Response Surface Methodology (RSM). Experiments were planned according to a three-factor central composite design (α=1.68), studying the influence of sucrose concentration, temperature and time, on the following parameters: volume ratio, water activity, color variation, weight reduction, solids gain, water loss and normalized moisture content, as well as total moisture, ash and fat contents. The experimental data was adequately fitted into second-order polynomial models with coefficients of determination (R2 ) from 0.716 to 0.976, adjusted-R2 values from 0.460 to 0.954, and non-significant lacks of fit. The optimal osmotic dehydration process conditions for maximum water loss and minimum solids gain and color variation were determined by the “Response Optimizer” option: 83% sucrose concentration, 20 °C and 9.2 hours. Thus, the best operational conditions corresponded to high sugar concentration and low temperature, improving energy saving and decreasing the process costs.
Teresa Delgado, Bruna Paim, Jose Alberto Pereira, Susana Casal, Elsa Ramalhosa
01.12.2017.
Professional paper
Energy pattern and conservations of condiment produced from soybean (Glycine max)
Energy being one of the largest operating expenses in most organizations especially manufacturing and processing industries leading to considerable scope for energy conservation and hence cost. Information on energy utilization and conservation pattern were obtained based on time taken, number of person involved and sources of energy using standard energy equations. A total of 445.40 ± 17.32MJkg-1 where thermal energy (420MJ ≈ 94%) and manual energy (25.40MJ ≈ 6%) were the only forms of energy used during production process. Conservation approach I resulted in mean energy of 72.08 ± 1.73MJkg-1 where electrical energy, manual energy and thermal energy accounted for 1.75MJ (3%) 7.34MJ (10%) and 62.99MJ (87%) respectively. Conservation approach II reduced the energy further to 57.24 ± 1.73MJkg-1 as the operation was thermal energy dependent, followed by manual and electrical energy with energy values of 48.13, 7.33 and 1.78MJ equivalent to 84.10%, 12.80% and 3.10% accordingly. Conclusively, traditional method of processing utilized highest energy (445.40MJ) followed by conservation approach I (72.08MJ) and conservation approach II (57.24MJ) was least in energy demand. Conservation approach II permits energy conservation to be 87% as compared with traditional method.
Ismaila B. Anjorin, Rahman Akinoso, Mayowa S. Sanusi