3:00pm - 3:20pm
Impact of concentration on the dynamic responses of flour dispersions from selected non-waxy rice.
Rheological responses of rice flour dispersions are essential for controlling process conditions, designing flow systems, estimating texture of foods and broadening utilization of rice-related materials. Dynamic shear rheological analysis is an excellent method used to characterize or classify the viscoelastic properties of macromolecular dispersions. The objective of our study was to determine the rheological behaviors of non-waxy Nigerian and Senegalese rice flour dispersions in steady and dynamic shear, and the effect of concentration on rheological properties. Steady and dynamic rheological responses of the rice flour dispersions were determined at different concentrations (4, 6 and 8%). All the rice flour dispersions exhibited a non-Newtonian shear thinning behavior. The power law model was used in expressing the correlation between concentration and apparent viscosity. Dynamic responses of the studied samples showed that Storage (G') and loss (G'') moduli both increased with increasing frequency (ɯ). The magnitudes of both G' and G" increased with increase in dispersion concentration. Dynamic rheological results exhibited a gel-like viscoelastic property with G' higher than G".
3:20pm - 3:40pm
Effect of solvent on lycopene extraction yield from tomato pomace
1Faculdade de Nutrição, Universidade Federal de Goiás (UFG), Goiânia, GO, Brazil; 2Process Engineering and Applied Science, Dalhousie University, Halifax, NS, Canada
This work evaluated the effect of solvent combination on the extraction yield of lycopene from tomato pomace, a by-product from industrial processing. The by-product, composed of tomato skin and seeds, was obtained from a tomato processing plant and freeze-dried. To 0.5g of the freeze-dried sample were added 30 mL of the extraction solvent, consisting of the following binary mixtures at a solvent ratio of 1:1 (v/v): hexane:acetone (HA), hexane:ethyl acetate (HE), ethyl lactate:acetone (EA) and ethyl lactate:ethyl acetate (EE). The extraction was performed in triplicate using a high performance homogenizer, at 20,000 rpm, for 15 minutes, at room temperature (25 ± 3 °C). The extract was vacuum-filtered, the extraction residue was recovered and re-extracted with another 20 mL of solvent for 15 minutes. The process was repeated once more, with 20 mL of solvent for 15 minutes. The three extracts were then combined and the lycopene content determined using a UV-vis spectrophotometer at 470 nm. The lycopene content of tomato pomace, in mg.kg-1 of dry weight, for each solvent mixture was: HA (515.1 ± 60.6), HE (494.9 ± 40.1), EA (690.8 ± 54.5), and EE (895.5 ± 83.1). In comparison with hexane, ethyl lactate improved extraction yield by 34% when combined with acetone, and by 81% when combined with ethyl acetate. The industrial tomato processing by-product had a high lycopene content, and would be suitable as a source material for lycopene extraction. Ethyl lactate improved extraction yield considerably, and would be a good alternative to hexane for lycopene extraction.
3:40pm - 4:00pm
Hydrodynamic kinetics and texture analysis of common beans during ultrasonic-assisted soaking
McGill University, Canada
Soaking of common beans has becoming an important pre-processing method to reduce cooking time and the anti-nutrients effects. This process can further be enhanced with Ultrasonication. In the present study, the hydrodynamic characteristics of three common beans cultivars were investigated. The impact of temperature, ultrasound amplitude and wave cycle on moisture transfer rate and kinetic parameters were evaluated. The Peleg’s model and the two-parameter Mitscherlich model were used to evaluate the comparative predicting capabilities of the bean hydrodynamic characteristics during ultrasonic-assisted soaking. Thermodynamic variations during the process were also presented.
4:00pm - 4:20pm
Enhancement of enzymatic hydrolysis in milk proteins using novel processing techniques
McGill Universsity, Canada
Milk is an indispensible source of nutrients for humans and is the first food given to the new born babies. It is an admixture of various nutritional components like fat, proteins, minerals and other trace elements which play a major role in human diet and nutrition. Milk protein contains two constituents namely caseins and whey protein. Caseins are again classified into αs1-Casein (12-15 g/L of milk), αs2-Casein (3-4 g/L of milk), β-Casein (9-11 g/L of milk), κ-Casein (3-4 g/L of milk) and γ-Casein (1-2 g/L of milk) whereas whey proteins are further classified into β-Lactoglobulin (2-4 g/L of milk), α- Lactoalbumin (1-1.5 g/L of milk), Bovine serum albumin (0.1-0.4 g/L of milk), Immunoglobulins (0.6-1.0 g/L of milk) and Proteose peptones (0.6-1.8 g/L of milk). Milk proteins also house major allergens. In North America, almost 2-3 percent of children under the age of 3 are suffering from milk allergy to which abstinence is the only solution. This implies that they are deprived of the basic nutrients that are important for their growth. The two major allergens in milk are β-Lactoglobulin and α-Lactoalbumin. Hence, our approach is to evaluate novel food processing techniques, both thermal and non-thermal processing in combination with enzymatic hydrolysis which can aid in reducing this milk allergy. This will be a boon to children of North America as it will fulfill the basic nutritional requirements required to lead an active and healthy life.
4:20pm - 4:40pm
Preprocessing Techniques for Hyperspectral Imaging Data
McGill University, Canada
Hyperspectral imaging (HSI) has shown great potential for rapid and nondestructive assessment of food quality and safety. Applications of the technique result in large data sizes with significant reductant variables. There are also multicollinearity, particle size variation and light scattering effects that present difficulty in predictive modelling. The goal of this study was to investigate the effectiveness of various preprocessing techniques that could be used to mitigate some of the challenges associated with HSI data. Different preprocessing techniques namely: PCA, SNV, OSC, MSC, log-normalization, 1st and 2nd derivatives, detrend, mean centering, and autoscaling were studied. HSI datacube obtained from chicken egg was used in the study and the ZeroR algorithm was implemented to estimate baseline performance for an eventual subsequent modelling. The results show that autoscaling, log-normalisation and OSC methods performed optimally in terms of observed classification accuracies, root mean square errors and percentage of information explained by various principal components. The said preprocessing techniques were then recommended for use in handling chicken egg hyperspectral data prior to a downstream multivariate analysis.
4:40pm - 5:00pm
Viscoelastic Properties of High Quality Cassava Flours
1University of Uyo, Nigeria; 2Lakehead University, Canada; 3McGill University, Montreal, Canada; 4Michael Okpara University of Agriculture, Umudike, Nigeria
The influence of temperature (30 - 70 °C) on the viscoelastic properties of high quality cassava flour (HQCF) from five varieties of cassava flours (TME 419, NR 8082, TMS 98/0581, TMS 98/87164, and TMS 98/1632) was studied using a controlled strain rheometer. The samples were prepared by adding distill water to cassava flour in the ratio of 3:1 (water : cassava flour). A small amplitude oscillation shear rheometer was used to study viscoelastic properties and other rheological characteristics. Isothermal heating of cassava pastes in the temperature range of 30 - 70 °C presented a systematic increase in storage modulus (G′) and loss modulus (G′′) with heating time. Another set of experiments were conducted to compare gel rigidity of the cassava flours. Fresh samples were isothermally heated to 80 °C and held for 30 min with and without time sweep and followed by immediate cooling to 25 °C after which the frequency sweep tests were carried out at 0.1–10 Hz. Different gel transition behaviors were observed across the cassava varieties. This study provides knowledge of different rheological behavior of high quality cassava flour from different cassava varieties that would be relevant for utilization of cassava gels on food applications.