Selection Models for the Internal Quality of Fruit, based on Time Domain Laser Reflectance Spectroscopy

Time domain laser reflectance spectroscopy (TRS) was applied for the first time to evaluate internal fruit quality. This technique, known in medicine-related knowledge areas, has not been used before in agricultural or food research. It allows the simultaneous measurement of two optical characteristics of the sample: light scattering inside the tissues and light absorption. Models to estimate non-destructively firmness, soluble solids and acid contents in tomato, apple, peach and nectarine were developed using sequential statistical techniques: principal component analysis, multiple stepwise linear regression, clustering and discriminant analysis. Consistent correlations were established between the two parameters measured with TRS, i.e. absorption and transport scattering coefficients, with chemical constituents (soluble solids and acids) and firmness, respectively. Classification models were created to sort fruits into three quality grades (‘low’, ‘medium’ and ‘high’), according to their firmness, soluble solids and acidity

Operation of an activated sludge plant for fellmongery wastewater treatment : a thesis submitted in partial fulfilment of the requirements of the degree of Master of Technology in Environmental Engineering at Massey University, Palmerston North, New Zealand

Activated sludge is one of the most common wastewater-treatment processes used to reduce pollutant loads on the receiving environment. For efficient operation, there must be an effective process control and operation strategy in place to ensure that process problems are avoided. This research is a case study into the process control and operation of an activated sludge plant used for fellmongery wastewater treatment. Analysis of the pretreated fellmongery wastewater showed that it is characterised by high total and volatile suspended solids concentrations, and high organic nitrogen concentrations. The plant was experiencing frequent problems that were attributed to the high influent suspended solids load coupled with ineffective solids management. Operation of bench-scale simulations showed that solids retention time (SRT) control at 5 or 10 days will produce acceptable effluent suspended solids concentrations and soluble chemical oxygen demand (COD) removal. Soluble COD removal for both 5 and 10 days was high at 85 and 80 % respectively at a hydraulic retention time of 6.4 days. Effluent suspended solids concentrations were 100 and 157 g/m 3 respectively. A steady state control model was developed based on, mass balances of biochemical oxygen demand (BOD) and volatile suspended solids (VSS), process performance equations, and the solids retention time (SRT). The model used three control points, the clarifier underflow pump, the clarifier influent pump and the waste sludge pump. The model was incorporated into an off-line Activated Sludge Operation Program (ASOP) to provide a user-friendly interface between the plant and operator. The main output from ASOP includes values for the three control points and suggestions to help avoid problems. A process control and operation strategy was developed using ASOP, the knowledge gained in this research, and an operation manual developed from accepted operation practises

Rheological and thixotropic behavior of banana (Musa cavendishii) puree

Some rheological properties of banana puree were investigated. Experimental data was fitted to Hahn, Weltmanand Figoni-Shoemaker equations in order to quantify the thixotropic behavior. Thixotropy measurements were carried out in a range between 5 and 75ºC and applying she arrates of 10 and 20 s-1, finding that, in all cases, the Figoni-Shoemaker relationship was the best one to model the time dependency response. The flow behavior was well fitted by the Herschel-Bulkley model in a range between 5 and 75ºC, and between 12 and 22 ºBrix, obtaining that consistency coefficient decreased with temperature and increased with soluble solids content, flow behavior index decreased with soluble solids content, and apparent viscosity decreased with temperature and increased with soluble solids content. Adjusting the variation of apparent viscosity with temperature by means of an Arrhenius-type equation, the activation energy was obtained for different soluble solids content

Changes of ultrasound characteristics of mango juice during fruit ripening

Attenuation and propagation velocity of ultrasound signals at 25 MHz were measured on clear mango juice samples using a pulse echo method. Ultrasound characteristics were determined with other physico-chemical characteristics on juice samples extracted from fruits undergoing ripening for three weeks at 23 °C and 80 % RH and periodically removed every two or three days. During fruit ripening, the changes of biochemical composition induced more effect on velocity than attenuation. Velocity were positively correlated to soluble solids content (R = 0.98), to sucrose content (R = 0.80) and negatively correlated to titratable acidity (R = -0.59) and fruit firmness (R = -0.76). A linear model based on soluble solids content and a PLS model based on all the physico-chemical characteristics were built to predict ultrasound velocity. Finally, the results obtained in this study showed that velocity is a relevant parameter linked to the major biochemical changes occurring during controlled fruit ripening. Due to high attenuation of ultrasound waves in mango peel and pulp tissues, confirmation of these results for whole fruit will be a challenge. (Résumé d'auteur

Genetic variation for bulb size, soluble solids content and pungency in the Spanish sweet onion variety Fuentes de Ebro. Response to selection for low pungency

The cultivar ‘Fuentes de Ebro’ is a long-day onion grown in the northeast of Spain, which is characterized by its succulence and low pungency. However, to match the market demand the size, pungency, and storability need to be improved. We have evaluated these quality-related bulb traits in 15 grower’s open-pollinated lines of this cultivar. Phenotypic variation observed for bulb weight, size and soluble solids content was significantly affected by location, growing season and line, while pungency depended on line and plot location. We found higher levels of genetic variation for bulb size and pungency than for soluble solids content, and significant phenotypic correlations indicated that milder onion tend to show larger size and lower soluble solids content. After one cycle of selection, we have obtained progeny with significantly lower pungency levels, and therefore, we estimated a realized heritability of 0.67. As conclusion, it is feasible to obtain a sweet cultivar after some selection cycles in the ‘Fuentes de Ebro’ onion, although considering indirect consequences in size and soluble solids conten

EVALUATING OPTIMAL PRODUCT MIX USING DYNAMIC SIMULATION: A TOMATO PROCESSING CASE

Technology-driven change is everywhere and value-capture from new technology is challenging for business managers. Also rival firms may use technology as part of major success strategies. This situation leads managers to be keenly interested in evaluation of alternative technologies prior to making a sunk investment in physical facilities. In contemplating new or added-capacity processing facilities, managers and investors must evaluate return on investment (ROI). Evaluation of ROI is complex because it varies by alternative technology and the resultant potential product mix alternatives associated with that technology at the time the investment capital is committed to build the processing plant. This research examines optimal alternative product mix from a processing plant technology that is fixed at the time of commitment to building or adding capacity. Evaluating the optimal product mix is of vital concern in any start-up processing environment. In this research the optimal product mix is evaluated by using a sophisticated evaluative tool known as PowerSim. This economic simulation software is used to model a start-up tomato processing plant in Ohio. The model evaluates the effects of various output, or tomato product mix, on plant profitability measured by ROI. Results indicate that an increase in plant profitability is expected when the tomato product mix consists of products that have a lower soluble solids concentration. The lower the soluble solids concentration of a tomato product, the less the processor will benefit from tomato varieties with high soluble solids. The processing operation achieves a RIO of 26.5 percent when the plant'Â’s product mix is 50 percent tomato paste (31 degrees brix) and 50 percent diced tomatoes. This product mix optimizes processor net income and realizes a plant return on equity of 50.6 percent.Agribusiness,

Effect of curing conditions and harvesting stage of maturity on Ethiopian onion bulb drying properties

The study was conducted to investigate the impact of curing conditions and harvesting stageson the drying quality of onion bulbs. The onion bulbs (Bombay Red cultivar) were harvested at three harvesting stages (early, optimum, and late maturity) and cured at three different temperatures (30, 40 and 50 oC) and relative humidity (30, 50 and 70%). The results revealed that curing temperature, RH, and maturity stage had significant effects on all measuredattributesexcept total soluble solids

Direct measurement of molecular mobility and crystallisation of amorphous pharmaceuticals using terahertz spectroscopy.

Despite much effort in the area, no comprehensive understanding of the formation and behaviour of amorphous solids has yet been achieved. This severely limits the industrial application of such materials, including drug delivery where, in principle, amorphous solids have demonstrated their great usefulness in increasing the bioavailability of poorly aqueous soluble active pharmaceutical ingredients. Terahertz time-domain spectroscopy is a relatively novel analytical technique that can be used to measure the fast molecular dynamics of molecules with high accuracy in a non-contact and non-destructive fashion. Over the past decade a number of applications for the characterisation of amorphous drug molecules and formulations have been developed and it has been demonstrated how this technique can be used to determine the onset and strength in molecular mobility that underpins the crystallisation of amorphous drugs. In this review we provide an overview of the history, fundamentals and future perspective of pharmaceutical applications related to the terahertz dynamics of amorphous systems

A note on the effect of calcium alginate coating on quality of refrigerated strawberries.

peer-reviewedAn alginate-based edible coating was investigated for the preservation of the quality of strawberries during cold storage (5 °C). Strawberries were immersed, successively, in sodium alginate and calcium chloride solutions to generate a surface coating of calcium alginate. The quality of coated and non-coated strawberries was evaluated by weight loss, visible decay, titratable acidity, total soluble solids and reducing sugar concentration over a 14-day storage period. Results showed that coating with calcium alginate had no significant effects on weight loss or physicochemical parameters when compared to control fruit, but it did result in the postponement of visible decay during refrigerated storage