Editorial: Sustainability of food resources and the supply chain

Food is essential to life, and it is one of the important factors that can affect human health. Other than that, it also affects the economy and, most importantly, the world’s resources. By 2050, the world population is expected to grow to 9.7 billion from its current 7.3 billion (UN DESA 2015). Considering the challenge of feeding 2 billion more people, our current food system is facing major sustainability challenges. It is expected that the world needs to produce about 70% more food to cater to the growth of the world’s population by 2050, which is referred to as the “food gap” (WRI 2014). It is a challenge for food producers and industries to close this “food gap” while at the same time maintaining sustainability in the food system. Three main food sustainability issues within the food system involve economic growth, social responsibility and environmental integrity. These issues include the security of food resources and supply, food safety, nutrition and health, alleviating poverty, affordability, quality, waste management, water and land management, climate change, biodiversity and many more

Factors Affecting Gluten Production And Its Rheological Characterizations

In this thesis, focus was given upon three factors affecting gluten production and development during dough mixing namely mixing time, salt levels and water levels. Gluten production was examined in terms of quantity and quality of gluten. Quantity of gluten was measured in terms of wet and dry gluten content. Wet gluten content was determined by weighing the gluten obtained from the dough washed under running tap water. The wet gluten was dried using air oven drying method to obtain dry gluten content. The quality of gluten was determined from the analysis of volume expansion, extensibility and rheological characterization. The volume expansion analysis was performed by frying the wet gluten in hot oil at 170 o C in deep fryer for 15 minutes. The volume of fried gluten was measured using mustard seed displacement method and the difference between the volume of fried gluten and the volume of wet gluten is measured as volume expansion of gluten.The main problem encountered in performing gluten and dough extensibility test is to hold the sample so that it does not break at the jaws that hold the sample. Thus it is one of the objectives in this study to build a simple set-up of tensile test to determine gluten extensibility, which is one of the most common measurements employed in determining the quality of gluten. A simple set-up of tensile test which is attached to Instron 5566 has been build to determine gluten extensibility. Gluten strip of about 10 mm x 10 mm x 70 mm was clamped at two ends using plastic clips and extended at the centre by hook at speed of 300 mm min -1 . Extensibility parameters such as original gluten length, gluten length at fracture, measured force, actual force acting on the gluten strips, strain and stress were obtained using the formulas derived from the results of tensile test. The tensile test set-up was successful in terms of providing the gluten extensibility measurements and also the gluten did not fracture at the clamping area. Rheological characteristics of gluten, K and n, were obtained by fitting stress-strain curve following an exponential equation, e s = Ken . Two types of flour, strong and weak, were used as a comparison. Correlation between two analyses measurements of the gluten quantity and quality are determined at the end of this thesis. An adequate polynomial equation model which fits the data was produced from Design Expert V.6.0.4. P-value, R 2 and lack-of-fit value were determined to verify the fitness of the polynomial model equation to the actual data and thus can be used as a good prediction of the data. The results from Design Expert were then transferred to Microsoft Excel file where the graph of the response was plotted against the three factors studied.Results suggested that from the three factors studied, salt gave the most significant effect (0.0001 < P < 0.02) on the gluten quantity and quality. As salt level increases, it decreases the wet and dry gluten content. The volume expansion of gluten and the extensibility seem to decrease with increasing salt level. This indicates that gluten network strength reduces and it does not mix into elastic dough as salt level increases. The next significant factor was water level (0.0001 < P < 0.67). Mixing time was the least significant factor among the three (0.0001 < P < 0.95). For all factors studied, the results for strong flour were higher than the weak flour in the quantity, volume expansion and also extensibility. This demonstrates that the quality of gluten is affected by the protein content of the flour. All correlations between two analyses of quantity and quality measurements show positive coefficient of correlation (R). Strong correlation between (i) gluten quantity and volume expansion (R > 0.75), (ii) gluten quantity and extensibility (R > 0.80) and (iii) volume expansion and extensibility of gluten (R > 0.60) were obtained for strong flour compared to weak flour (R > 0.45; R > 0.50; R > 0.30, respectively). These results indicate that the quality of gluten is influenced by the protein content of the flour and the extensibility and volume expansion of gluten is positively correlated. These correlations could be used in the food industry to improve the gluten quantity and quality in the future

A review on rheological properties and measurements of dough and gluten

The field of rheology has seen a wider application in the food industry recently although, it is a complex concept and that most food systems possess non-ideal characteristics. Nevertheless, the rheological behavior of foods are able to be determined using various techniques and equipment. Studies on rheological properties related to dough and gluten are often challenging due to its variance in nature and high dependence on many factors. This study attempts to give a review on the various types of experimental techniques and set-up used in quantifying rheological properties of dough and gluten. The rheological properties are defined and the behaviors are described by inducing stress and strains in small and large deformation studies

Development of gluten extensibility measurement using tensile test

Gluten is a viscoelastic mass obtained from washing wheat flour dough. A simple set-up of tensile test was built to determine gluten extensibility, which is one of the most common measurements used in determining the quality of gluten. The main problem encountered in performing gluten and dough extensibility test is holding of the sample so that it breaks within the sample and not at the jaws that hold the sample. In this research, gluten strips of about 5.0 ± 0.5 g were clamped to the set-up which was attached to Instron 5566 series and then extended at the centre by a hook at crosshead speed of 300 mm min-I. Extensibility parameters such as original gluten length, gluten length at fracture, measured force, actual force acting on the gluten strips, strain, strain rate and stress were obtained using the formulas derived from the results of measurements. The performance of gluten extensibility between strong and weak flour dough were compared. The results of the study showed that gluten obtained from strong flour has greater extensibility compared to weak flour

Extraction and characterisation of pectin from dragon fruit (hylocereus polyrhizus) peels

Pectins are complex carbohydrate molecules that are used in numerous food applications as a gelling agent, thickener, stabiliser, and emulsifier. Dragon fruit (Hylocereus polyrhizus) is one of the tropical fruits that belong to the cactus family, Cactaceae. Since the peels of dragon fruit are often discarded as waste, it would be an advantage to convert it into a value-added product such as pectin. The objective of this study was to investigate the extraction of pectin from dragon fruit peels under different extraction time using hot water extraction method. The dragon fruit peels were extracted using distilled water at 80 °C with different extraction time of 20, 40, 60 and 80 min. The extracted pectin was characterised by its yield, moisture and ash content, degree of esterification and antioxidant activity. Determination of moisture and ash content was conducted using AOAC standard method. The determination of the degree of esterification of pectin was performed using Fourier Transform Infrared Spectroscopy (FTIR). DPPH assay was used to determine the antioxidant activity of the pectin extract. Based on the result, the yield of pectin decreases (20.34 to 16.20 %) with the increase of extraction time, moisture contents were between 4 to 6 % while ash contents were between 7 to 10 %. Pectin from dragon fruit peels was determined as low methoxyl pectin and has high percentage of antioxidant activity with low value of inhibition concentration (IC50) (0.0063 to 0.0080 mg/mL). 60 min extraction sample exhibits the highest antioxidant activity (81.91 % at 40 μg/mL), followed by 80 min extraction (81.68 % at 40 μg/mL), 40 min extraction (81.38 % at 40 μg/mL) and 20 min extraction (81.31 % at 40 μg/mL)

Characterization of thermostable beta-1,4-galactanase and its application in hydrolysis of pectin from sweet potato (Ipomoea batatas (l.) lam) peels

Galactooligosaccharides (GOS) synthesis has received much attention due to its prebiotic function. Beta-1,4-galactanase responsible for the hydrolysis of galactan plays an important role in producing GOS from biodegradation of this pectin component. In this study, beta-1,4-galactanase (BgcGC) from a thermophilic Geobacillus mahadii Geo-05 was heterologously expressed in Escherichia coli (E. coli) and characterized. The optimum temperature of BgcGC was at 60°C and stable from 20-60°C while optimum pH was at 6 and stable from pH 4-10. BgcGC showed high catalytic efficiency towards potato galactan (873.8 ml mg-1 s-1) and lupin galactan (1694.4 ml mg-1 s-1). The activity of BgcGC was not significantly affected with the presence of 100 mM K+, Tween-20 and 2-mercaptoethanol. Application of BgcGC towards pectin-containing galactan oligomer extracted from sweet potato peels resulted in galactose and GOS synthesis as revealed by high performance liquid chromatography analysis. Thus, this enzyme has a potential to be one of the enzyme candidates involves in pectin complex degradation to produce GOS

Statistical modelling of gluten production by varying mixing time, salt and water levels during dough mixing.

Gluten is widely discussed in dough and breadmaking subjects but the focus has not been on the production of gluten itself for usage and application in the food industry. This paper presents some modelling studies of gluten production using response surface methodology (RSM) by varying three main factors that contribute towards gluten formation during dough mixing, which are the mixing time, salt and water levels. The gluten produced was measured for its quantity in terms of wet and dry gluten contents and for quality, in terms of volume expansion of fried gluten and extensibility of gluten. Two wheat flour types, the strong and weak were used as comparison. The experiment was designed following a standard RSM design, known as the central composite design. The results of analysis of variance indicated that the proposed mathematical model obtained can adequately describe the production of gluten within the studied factor limits. The coefficient of determination, R2 of all the responses were higher than 0.80. Results show that salt gave the most significant effect (0.0001<P<0.02), followed by water level (0.0001<P<0.67) and the least significant factor was mixing time (0.0001<P<0.95)

Extraction of Swietenia macrophylla Seed Oil using Supercritical Carbon Dioxide Technique and Its Antioxidant, Antidiabetic and Toxicity Properties

Abstract: Swietenia macrophylla has been used in treatments for diabetes, asthma, premenstrual syndrome and migraine traditionally. The seeds of S. macrophylla have been proven to possess antioxidant, antimicrobial, antifungal and hyperglycemic activity. Supercritical carbon dioxide (SC-CO2) extraction is a recent extraction process technology that has been developed to provide better extraction yield, safer and easier process. This study aimed to extract S. macrophylla seed oil by using SC-CO2 and investigate the antioxidant, antidiabetic activity and toxicity content of the oil extracted. Antioxidant analysis was performed by using 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical scavenging activity and in vitro antidiabetic analysis was done by using the inhibitory of a-amylase and a-glucosidase to validate antidiabetic activity of S. macrophylla seed oil. Toxicity test of S. macrophylla seed extract was performed using MTT assay on human skin fibroblast cell (HSF 1184). The result showed that S. macrophylla seed extracts at studied concentrations of 10 to 0.0001 mg/mL are non-toxic with cell viability above 80 %. a-amylase and a -glucosidase inhibition (%) of the S. macrophylla seed extracts was 100.0 ± 0.3 % and 4.1 ± 2.0 %. S. macrophylla seed extract was proven to have promising antidiabetic activity to act as an alternative to the commercial antidiabetic drugs