In conventionally-designed buildings for finishing pigs, extreme weather conditions can impact negatively on feed utilisation and animal welfare. The SPaTHE (Solar, Passive, Thermal, Heat Exchange) ...concept is an innovative, resource-efficient engineered building designed to provide an internal environment where finishing pigs can thrive. Passive design elements include solar shading and capture combined with integrated earth tubes to facilitate heat exchange with incoming fresh air to reduce extreme summer and winter internal temperatures. The SPaTHE specification was dynamically modelled and compared to an existing conventional finisher building operating in the UK. The same dimensions (18 m × 14 m) and build specification were used for each building, which was designed to hold 292 pigs from 20 to 100 kg liveweight. Results showed that pigs in the optimum configuration of conventional building form spent 661 fewer h y−1 in conditions <19 °C, and 102 fewer h y−1 in conditions >28 °C than with a standard building. Whereas with the SPaTHE design, during 2222 h y−1 the pigs were kept at optimum conditions between 19 °C to 22 °C. The model also estimated that the SPaTHE design would reduce the peak summer internal operative temperature by 3.4 °C when the external temperature was 28 °C, and increase the peak winter internal operative temperature by 1.2 °C when the external air temperature is −5.4 °C. Hence the concept design potentially provides an environment which more closely matches the needs of finishing pigs and thus may contribute to more sustainable food production systems.
•Innovative building design potentially improves resource use and pig welfare.•Model was validated by comparison with data from an existing conventional building.•Passive design and earth tube provide a more optimum environment for finisher pigs.•Engineered approach to sustainable housing for optimised pig production.
Improved (high yield and disease resistant) cassava varieties were introduced into Ethiopia around the onset of the twenty-first century, as a potential food security crop. At present, limited ...information is available from the country on post-production aspects of the value chain (VC) and related food losses. The lack of such data prevents policymakers and VC actors from taking steps towards improving VC efficiencies, which can have a significant impact on livelihoods and food security. The focus of this study was to examine the prevailing post-harvest practices in the cassava VC in southern Ethiopia and quantify the extent of food losses and associated by-products in the framework of the recently developed ‘food loss and waste protocol’. The majority of the cassava in the study area was processed into dry chips and milled into a composite flour with teff and maize to prepare the staple bread (
injera
). ‘Critical loss points’ were during sun-drying (4%) and stockpiling at farm and marketplace (30–50%). Insect pest damage was primarily responsible for food losses at farm and market level. The most important insect species infesting dry cassava were identified during the survey. As far as the by-products were concerned, the ratio of leaf:wood (stem and stump):starchy root on a dry matter basis at harvest was 1:6:10. Further emphasis should be on improving processing and storage technologies to reduce food losses and the better recovery and utilisation of by-products, especially the leaves of cassava, which could be a potential source of protein in human diets.
•The drying of purple-fleshed Cocoyam exhibits a 2-stage falling rate behaviour.•The dying kinetics are best described by the Two-Term Exponential model.•Blanching and chemical pre-treatments improve ...the rehydration ratio.•Blanching and chemical pre-treatments don’t improve drying time and drying rate.•Blanching and chemical pre-treatments don’t improve colour and energy consumption.
This study investigated the drying behaviour of purple-speckled Cocoyam and the effect of drying temperature (40 °C, 60 °C and 75 °C), slice thickness (4 mm, 7 mm and 10 mm) and pre-treatments (blanching in boiling water for 3 min, blanching in boiling water for 3 min followed by dipping in 0.1 per cent sodium metabisulfite for 5 min) and non-pre-treated slices. The process and quality criteria under consideration included the total drying time, rehydration ratio, colour difference, browning index and specific energy consumption. The drying air velocity was maintained constant at 0.6 m/s while the relative humidity was monitored to average 5 – 10 per cent inside the drying cabinet during the experiments.
The drying process exhibited a 2-stage falling rate behaviour with kinetics best modelled by the Two-term Exponential, Peleg and Midili models. Non-pre-treated Cocoyam slices performed better than pre-treated slices in terms of decreased drying time, total colour change (ΔE), browning index (B.I) and specific energy consumption (Es) with the exception of rehydration ratio (RR) for all factor settings. The pre-treatment process was found to impart irreversible changes to the material that negatively impacted the majority of the quality attributes considered. The combined effect of both pre-treatments and hot air drying should therefore be evaluated to comprehensively take into account the total changes the entire process imparts on the material. Numerical optimisation results revealed that the most suitable drying conditions were at a drying temperature of 75 °C, slice thickness of 4 mm and without pre-treatment, which yielded a composite desirability index of 0.78. These settings resulted in a total drying time of 109 min, a total colour difference of 2.4, browning index of 9.96, rehydration ratio of 0.7 and specific energy consumption of 6119.3 kJ/kg.
This paper investigates the potential for incorporation of human commercial building design modelling into the pig production industry. During the last decades pig building design has relied heavily ...on building manufacturers compared to human commercial buildings that regulate standards to improve the sustainability of the building. Thus, the aim of this paper was to gain a greater understanding of the design requirements for sustainable forms of pig housing, which could potentially improve the welfare of the pig and promote greater resource use efficiency. Part of an existing mechanically ventilated UK pig production building, which represents three adjacent fully-slatted units each capable of holding approximately 292 pigs and measuring approximately 18m x 14m, was used as a basis to create a dynamic thermal model of the building. The model takes into account the possibility of future rises in environmental temperature and the effect of this climate change on building performance and pig growth, feed efficiency and welfare. The results of the model showed that as the finishing pigs increased in size they have the potential to be subject to increasingly poor indoor air quality, during the winter months. The model also shows that improving the thermal properties of the building not only helps with reducing the amount of time that the pigs could potentially spend at extreme low temperatures, by approximately 1115h (46days), but can also help with reducing the number of hours the pigs spend above 26°C during the summer months, by approximately 8h.
Orange-fleshed sweet potato (OFSP) and pumpkin fruit are underutilized crops with great potential for the production of high-quality bread with health-enhancing properties. However, the incorporation ...of nonconventional flour in bread formula may influence the dough and bread quality properties. This study investigated the effect of partial substitution of wheat flour with OFSP (10–50%) and pumpkin flour (10–40%), baking temperature (150–200 °C) and baking time (15–25 min) on the quality properties of the composite dough and bread using response surface methodology (RSM). Dough rheological, bread physical and textural properties were analyzed, modelled and optimized using RSM. Satisfactory regression models were developed for the dough and bread quality attributes (R
2
> 0.98). The dough development time, crust redness, hardness, and chewiness values increased while optimum water absorption of dough, specific volume, lightness, springiness, and resilience of bread decreased significantly (p < 0.05) with increasing incorporation of OFSP and pumpkin flour in the bread formula. Additionally, the specific volume, crust redness, crumb hardness, and chewiness of the composite bread increased significantly (p < 0.05) with increasing baking temperature from 150 to 180 °C but reduced at higher baking temperatures (≥ 190 °C). The staling rate declined with increased OFSP and pumpkin flour whereas increasing the baking temperature and time increased the bread staling rate. The optimized formula for the composite bread was 78.5% wheat flour, 11.5% OFSP flour, 10.0% pumpkin flour, and baking conditions of 160 °C for 20 min. The result of the study has potential applications in the bakery industry for the development of functional bread.
Graphical Abstract
The influence of two different control strategies, constant air temperature and constant product temperature, on product quality and drying behaviour of apples was investigated. The interactions of ...the drying parameters air temperature (35–100 °C), product temperature (35–85 °C), dew point temperature (5–30 °C) and air velocity (2.0–4.8 m/s) with drying time, colour changes and shrinkage were measured continuously and determined for both strategies. Based on these results the two strategies were compared with regards to their effect on drying performance.
The results show that the drying strategy has a significant influence not only on the development and duration of the drying process but also on the development of colour changes and shrinkage. Controlling product temperature led to shorter drying times and generally lower colour changes. Furthermore, it was shown that the product temperature develops characteristically; two stages and a clearly visible transition period can be detected. This potentially can be used to control the process and, therefore, improve its performance regarding duration and quality aspects.
•Development of quality attributes significantly depends on control strategies.•Online measurements show that information can be used for process control optimisation.•Product temperature controlled drying is gentler at comparable drying times.
Since the 1970s prices for fuel and raw materials have steadily risen. This development has put the brewing industry under pressure to reduce production costs by intensifying their production ...process. Additionally in recent years environmental concerns over green house gas emissions and climate change have arisen amongst consumers and legislative requirements are getting stricter. Because of these developments, small and medium-sized breweries are increasingly forced to apply strategies for economic, environmental and social sustainability, too.
This paper gives an overview over the state of the art in the brewing industry commonly realised in large breweries and presents important barriers to efficiency in smaller companies. The production process of a typical medium-sized brewery in the UK was analysed to identify principal measures to reduce energy and water demand. The case study also examines the particular problems preventing the brewery from realising these measures. The analysis of the process shows that even basic and easily applicable efficiency measures have so far been neglected. Improving insulation and implementation of basic heat recovery measures could potentially reduce energy demand by 20% and would result in a payback period of 1.3 years.
•Heat transfer of whole sweet potato roots under forced-air cooling and heating is investigated.•Experiments were carried out in a cooling and heating chamber.•The cooling and heating rate and time ...was clearly depended on air velocity and roots size.•Simulated and experimental data on cooling and heating times were compared for validation.•Simulation results quantitatively agreed with experimental results.
In this work, we investigated how different air velocity and temperature affect the cooling and heating rate and time of individual sweet potato roots. Additionally, we modified and applied a simulation model which is based on the fundamental solution of the transient equations for estimating the cooling and heating time at the centre of sweet potato roots. The model was adapted to receive input parameters such as thermo-physical properties of whole sweet potato roots as well as the surrounding air properties, and was verified with experimental transient temperature data. The experimental results showed that the temperature at the centre and the under skin of sweet potato roots is almost homogeneous during forced convection cooling and heating. The cooling and heating time was significantly (P<0.05) affected by high air velocity and sweet potato root size. The simulation results quantitatively agreed with the experimental transient data. This research, thus provides a reliable experimental and theoretical basis for understanding the temperature variations as well as estimating the cooling and heating times in individual sweet potato roots under forced convection cooling and heating. The result from this study could be applied to design and optimize forced-air treatment equipments with improved energy efficiency as well as ensuring safety and the maintenance of sweet potato roots quality.
Initial quality grading of meat is generally carried out using invasive and occasionally destructive sampling for the purposes of pH testing. Precise pH and thresholds exist to allow the ...classification of different statuses of meat, e.g. for detection of dry, firm, and dark (DFD) (when dealing with cattle and sheep), or pale, soft exudative meat (when dealing with pork). This paper illustrates that threshold detection for pH level in beef with different freshness levels (fresh, fresh frozen-thawed, matured, and matured frozen-thawed). Use of support vector machine (SVM) analysis allowed for the classification of beef samples with a pH above 5.9, and below 5.6, with an accuracy of 91% and 99% respectively. Biochemical and physical conditions of the meat concerning the pH are discussed.
•A novel non-invasive approach for pH thresholding of beef is presented.•The classification model exhibits a robust detection of beef meat with high pH even under different freshness conditions.•The biochemical and physical aspects of DFD meat and in conjunction with their spectral response are thoroughly discussed.
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