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Volume 13, Issue 2, 2024

Online ISSN: 2182-1054

Volume 13 , Issue 2, (2024)

Published: 18.10.2024.

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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

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

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

18.10.2018.

Original scientific paper

‘Made-in-transit’ yoghurt processing: a review of basic concepts and technological implications

The manufacture of food during distribution, a concept known as “made-in-transit” (MIT) manufacture, has the potential to expand the distribution range, extend shelf-life, and provide the customer with the freshest possible product. Benefits for the manufacturer include maximising throughput while minimising manufacturing space and inventory. This concept is new, with mushrooms being the only MIT food developed so far. The feasibility of developing an MIT product from a fermented food was reviewed using yoghurt as a model system. Through the alteration of some of the yoghurt manufacturing parameters (e.g. milk base formulation, heat treatment, starter culture composition and fermentation temperature) it is possible to develop this form of yoghurt production. A predictive microbiology approach is suitable for predicting the effects of both time and temperature on designing and predicting the fermentation process. This review demonstrates the potential of the MIT concept for a fermented food.

Nor Khaizura Mahmud Ab Rashid, S. H. Flint, O. J. McCarthy, J. S. Palmer, M. Golding, A. Jaworska

01.12.2017.

Professional paper

Quality assessment and shelf life modeling of pulsed electric field pretreated osmodehydrofrozen kiwifruit slices

The objective of this workwas to investigate the potential use of pulsed electric field (PEF) in combination with osmotic dehydration (OD) as a pre-freezing step and to evaluate the effect on quality characteristics and shelf life of frozen kiwifruit. Peeled kiwifruit was subjected to PEF (1.8 kV/cm), sliced and treated in OD-solution [containing glycerol, maltodextrin, trehalose, ascorbic acid, calcium chloride, citric acid, sodium chloride; 1/5 (wfruit/wsolution)] for 30 and 60 min at 35 °C. Combined, PEF only and OD only treated samples as well as nontreated and blanched (80 °C, 60 s) samples were frozen and stored at constant (-5, -10, -15, -25 °C) and dynamic temperature conditions (-18 °C-3 d, -8 °C-2.5 d, -15 °C-3 d). Quality of frozen samples was evaluated by means of drip loss, colour, texture, vitamin C and sensory evaluation (1-9 scale); and shelf life (SL) was calculated. Nontreated and blanched samples presented high drip loss and tissue softening (instrumentally measured as Fmax decrease). The tissue integrity was well retained in all osmotically pretreated samples. PEF pretreatment caused increase of fruit whiteness (increase of L value) and yellowness (a and/or b value increase); SL calculation was based on colour change. All OD samples had high vitamin content (24.6 mg/100 g fresh material compared to 138-154 mg/100 g osmodehydrated material); PEF led to 93% (of the initial) vitamin retention; blanched samples showed the lowest retention (86.9% of the initial) (criteria for SL calculation). OD and combined PEF-OD treatment increased the shelf life of frozen kiwifruit (up to 3 times; based on sensorial criteria). The developed kinetic models for colour change, vitamin loss, and sensory quality deterioration were validated at dynamic temperature conditions. PEF pretreated OD (at significantly shorter time, 30 min compared to 60 min) kiwifruits retained optimum quality and sensory characteristics. PEF and OD could be used as a preprocessing step of good quality, longer shelf life kiwi sliced frozen products.

Efimia Dermesonlouoglou, Ismini Zachariou, Varvara Andreou, Petros S. Taoukis

01.12.2017.

Professional paper

Effect of storage time and gamma irradiation on the chemical properties of olive (Olea europaea) oils

The objective of this study was to investigate the effects of gamma irradiation at doses of 0, 1, 2 and 3 kGy, and storage time of olive fruits for 0, 30 and 45 days on changes in chemical properties of olive oil during storage periods of 0, 6 and 12 months. The initial acidity value (AV), peroxide value (PV), Thiobarbituric Acid (TBA), phenolic content, iodine value (IV), and saponification value (SV) of virgin olive oil obtained from olives fruits immediately after harvest (at day zero) were 1.04%, 3.06 mEqO2 kg-1oil, 0.025 mg MDA kg-1 oil, 314.71 mg gallic acid kg-1 oil, 93.38 gI2 100 g-1 oil and 194.88 mg KOH g-1 oil, respectively. In general, the AV and PV of olive oil was increased by gamma irradiation, while the phenolic and IV of olive oil was deceased by gamma irradiation and storage time. The TBA value and SV of olive oil was not significantly (p>0.05) changed by gamma irradiation.

M. Al-Bachir

18.10.2018.

Original scientific paper

A nutritional evaluation of the berry of a new grape: 'Karaerik' (Vitis vinifera L.)

Grape berries are a good source of nutrients and nutraceuticals and have many benefits for human health. Growing interest in the export potential and consumption of a new grape (cv. Karaerik), cultivated as a table grape in Turkey, encouraged us to profile its major nutrient contents from six different locations. Due to its popularity, the nutritional value of this grape berry needs to be investigated to ascertain its potential economic and health benefits. The most abundant sugars in the grape berry were fructose and glucose (peel/whole fruit; averages 236.57 and 127.87, and 183.36 and 108.60 (g kg-1 fresh weight), respectively), while the major organic acids were tartaric and malic acids (7.17 and 2.81, and 2.61 and 1.76(g kg-1 fresh weight), respectively). Linoleic acid (peel/whole fruit/seed; 37.14, 33.12 and 57.83%, respectively) was the predominant fatty acid, while potassium (peel/whole fruit/seed; 9331.5, 10226.33 and 5354 mg/g dry weight, respectively) was the predominant mineral, followed by phosphorus (1592.8, 2672 and 3072.67) in the berry. Our results demonstrate that the nutrient components and physicochemical parameters varied significantly among the sampling locations. The grape berry contains considerable quantities of potentially beneficial healthy nutrients worthy of further evaluation.

Aynur Kurt, Nesrin Colak, Aydin Sükrü Bengu, Ali Gundoğdu, Erdal Akpınar, Sema Hayirlioglu-Ayaz, Faik Ayaz

18.10.2018.

Original scientific paper

Are we doing our homework? An analysis of food engineering education in Brazil

What is the profile of Food Engineering education in Brazil? Are we following the contemporary professional renewal trend? Driven by these questions, the present study analyzed data regarding 21 academic courses, which represent approximately 22% of the total bachelor’s degree in food engineering courses offered in the country. Samples were defined considering a Brazilian annual ranking of undergraduate programs: very good (four stars) and excellent (five stars). Next, information was recovered from both the Brazilian Ministry of Education and institutional homepages of each analyzed program. The results suggest that food engineering programs exhibit relative identity, naturally due to their history and the path of each program and their faculty, shaping particularities in how fields of knowledge are constituted, in addition to their representativeness in the total workload of the program. However, initial analysis is suggestive regarding understanding that Brazil is not properly doing its homework, based on global movement, concerning food engineering education. The need to rethink Brazilian technical education, without culminating in additional workload, is emphasized, not only regarding new materials and technologies for learning and teaching, but also in terms of bringing a human and market approach. The achievement of this complex goal seems to be provided by the encouragement of student associations, transversal learning processes, and learning experiences outside the classroom as a means of improving undergraduate programs and human resources.

Vivian-Lara Lara Silva, Fausto Makishi, Marcus Magossi, Izabel Cristina Freitas Moraes, Carmen Silvia Favaro Trindade, Paulo Jose do Amaral Sobral

18.10.2018.

Original scientific paper

Physicochemical and antioxidant properties of banana varieties and sensorial evaluation of jelly prepared from those varieties available in Sylhet region

The present research aimed to evaluate and compare the antioxidant activity in both pulp and peel and the physicochemical contents in the pulp of four local varieties of banana, i.e. Musa acuminata species named Sagor, Champa, Shail and Bichi, available in Sylhet region of Bangladesh. The antioxidant activity from a methanolic extract of banana peels and pulps was evaluated by determination of total phenolic content and DPPH scavenging activity. The physicochemical contents of banana pulp such as protein, fat, moisture, ash and carbohydrate were also determined. The results showed that the overall antioxidant activity of banana peel was higher than the pulp of banana. The pulp of the Shail variety had the highest antioxidant activity (TPC = 80.14 mg GAE/100 g, DPPH radical scavenging activity =91.37%) among the four varieties. Fat (1.38%) and moisture (76.23%) contents were higher in the pulp of Shail, while protein (1.82%) and carbohydrate (22.71%) contents were higher in the pulp of Bichi. The Champa variety contained higher ash content (1.05%). Among the jellies prepared from those banana varieties, the jelly of the Shail variety showed the highest score for overall acceptance (6.8) whilst the jelly prepared from the Bichi variety showed the highest score for taste (7.75). This may be due to higher carbohydrate content. The study suggests that banana peel could be used in the food industry as a raw material to produce bakery products and in cosmetics and pharmaceutical industries as an antioxidant supplement.

Abdullah A. Sad, M. M. Hoque, Wahidu Zzaman

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