Food Engineering

The proximate composition of skinned farmed African freshwater catfish (Clarias gariepinus) fillet was determined and found to be moisture (77.2%), protein (17.12%), ash (1.53%), lipid (3.39%) and carbohydrate (0.75%). The density, specific heat, thermal conductivity, thermal  diffusivity and latent heat obtained as functions of the proximate  composition of the fillet were 1059 kgm-3, 3.63 kJkg-1K-1, 0.525  Wm-1K-1, 1.2 x 10-4m2s-1 and 258.62 kJkg-1 respectively. The thermo-physical values obtained were correlated with the proximate composition value, the specific heat, thermal conductivity and latent heat increased with increase in moisture content while thermal diffusivity decreased as  moisture content increased. The density had positive correlation with ash and carbohydrate contents but had inverse relation with protein, lipid and moisture contents. It also had weak inverse relation with thermal diffusivity and latent heat. Thermal conductivity had positive correlation with moisture content but had inverse relation with lipid content and weak relation with ash content. Heat may be transferred better along the fibres of the fillet than across the fibre.

Emulsification step of flaxseed oil microencapsulation was optimized using the Box-Behnken design of the response surface methodology in wall material concentration, oil loading and ultrasonic emulsification time. The optimization was performed to optimize the microencapsulation efficiency (MEE) and product yield (PY). Bulk density, particle size and hygroscopicity of the microcapsules were additionally determined. MEE showed a positive correlation with wall material concentration and ultrasonication time; however, increasing oil loading had an adverse effect. PY was mainly affected by wall material concentration and increasing the wall material concentration resulted in lower product yield. Longer ultrasonication time decreased particle size of the flaxseed oil emulsion, but particle size of the microcapsules did not significantly change. The particle size of the microcapsules was increased by increasing wall material concentration. Optimum conditions for the microencapsulation of flaxseed oil were predicted as a wall material concentration of 20 g.100 g- 1, a oil loading of 20 g oil.100 g- 1 wall material and an ultrasonication time of 120 s and this conditions provided 92.4% MEE and 68.7% PY. For practical conditions, wall material concentration of 20 g.100 g- 1, oil loading of 35.1 g oil.100 g- 1 wall material and ultrasonication time of 120 s can be suggested in the flaxseed oil microencapsulation process.

"http://www.researchmoz.us/cooking-sauces-pasta-sauces-and-stocks-uk-december-2013-report.html


Slow-simmered pasta sauces offer another potential means of supporting growth in the Italian sector, as 28% of users state they would pay more for these, despite them being largely absent in the UK market. This slow-cooking method for pasta sauce has connotations of authentic cooking, and is well-placed to appeal to time-starved consumers who lack the time to prepare a pasta sauce in such an authentic way.
"

A study was carried out on the impact of storage structures and soil sodicity on vitamin C contents of stored oranges. Three sets of four different types of passive evaporative cooling structures made of two different materials, clay and aluminium were constructed. One set consists of four separate cooling chambers. Two cooling chambers were made with aluminium container (round and rectangular shapes) and the other two were made of clay container (round and rectangular). These four containers were separately inserted inside a bigger clay pot interspaced with clay soil of 5 cm (to form tin-in-pot, pot-in-pot, tin-in-wall and wall-in wall) with the outside structure wrapped with jute sack. The other two sets followed the same pattern with interspacing of 7 cm and 10 cm respectively. The set with 7 cm interspace served as the control in which the interspace soil and the jute sack were constantly wetted at intervals of between 2 to 4 hours depending on the rate of evaporation with water at room temperature. The other two sets (5 cm and 10 cm interspaced soil) were constantly wetted with salt solution (sodium chloride, NaCl) at the same interval to keep the soil in moist condition. In addition, the control has no fans and the inner cooling chambers were not lined with polyethylene nylon while the other two sets have fans and their inner cooling chambers lined with polyethylene nylon. Freshly harvested oranges were used for the experiment and the temperature and relative humidity of the storage chambers and the ambient were monitored on daily basis at 8.00am, 12 noon and 6.00pm while the vitamin C contents were determined at interval of three days for a period of three weeks. The oranges kept inside the tin-in-wall and wall-in-wall structures in all the three interspaces retained the highest amount of vitamin C at the end of the storage period. The vitamin C values of 32.42 mg/100ml, 30.68 mg/100ml, 33.98 mg/100ml and 34.94 mg/100ml were recorded for the tin-in-pot, pot-in-pot, tin-in-wall and wall-in-wall respectively for the 5 cm soil interspace. The vitamin C values of 31.78 mg/100ml, 30.80 mg/100ml, 32.94 mg/100ml and 33.32 mg/100ml were recorded for the tin-in-pot, pot-in-pot, tin-in-wall and wall-in-wall respectively for the 7 cm soil interspace while the vitamin C values of 31.54 mg/100ml, 31.16 mg/100ml, 33.42 mg/100ml and 33.54 mg/100ml were recorded for the tin-in-pot, pot-in-pot, tin-in-wall and wall-in-wall respectively for the 7 cm soil interspace. Overall, the 7 cm soil interspace structures recorded the least amount of vitamin C of 128.84 mg/100ml while the 5 cm and 10 cm soil interspace structures recorded higher values of vitamin C contents of 132.02 mg/100ml and 129.66 mg/100ml respectively.

Hardness is a kernel characteristic that influences both milling and processing characteristics of wheat. It is one characteristic that is used for segregating wheat to meet the needs for various products. Kernel virteousness is a visual marker for hardness and is the characteristic assessed during the grading process. The potential of classifying vitreous and non-vitreous durum wheat kernels, in crease-down position, using imaging systems based on real time soft X-rays or transmitted light was assessed in this study. Durum wheat kernels at 14, 15 and 16% moisture contents were used as samples in this study. Image features modeling gray level distribution, textural and shape moments were measured and used to develop a classification system for vitreous and non-vitreous durum wheat kernels. The classification accuracies were 76% for vitreous kernels and 82% for non-vitreous kernels at 16% moisture content using the soft X-ray system but for the transmitted light system, the classification accuracies were 86% for vitreous and 93% for non-vitreous kernels. Moisture content had no effect on classifying vitreous or non-vitreous kernels by the transmitted light system but the classification accuracies increased with moisture content for non-vitreous kernels by the soft X-ray system.

A central composite design (CCD) with three variables was used to study the response pattern and to determine the optimum combination of the variables. CCD combines vertices of the hypercube whose co-ordinates are given by a 2n factorial design and two star points (outsider points) to provide for the estimation of curvature of the model. Microwave conditions were optimized by using RSM. Four conditions optimized using overlaid contour plot, response optimizer and based on similarity only two conditions were considered for validation (Watt: 524, Watt/g: 19.371, Time: 191 sec; Watt: 540.02, watt/g: 19.343, Time: 194 sec). After validation ascorbic acid and capsaicin were analyzed by using HPLC. From HPLC analysis the ascorbic acid retention was calculated as 90.062 ± 0.023% and 92.34 ± 0.027% respectively. : For capsaicin standard the retention time is 4.538 minutes with peak area 5742043, but nearby that particular retention no peaks are coming for red bell peppers either raw or blanched one. So we may conclude that red bell pepper is not having capsaicin in it and the same was also reported in earlier researches also. The β-carotene retention content in slices blanched at optimized MW blanching conditions was also estimated which was 0.04±0.0039 mg/g (dry weight) for raw, 0.0249±0.0047 mg/g (dry weight) and 0.0318±0.0033 mg/g (dry weight) for blanched samples at optimized conditions respectively. From gas chromatogram and it can be concluded that volatile linalool retention time is approximately 36 minutes and we can conclude that in raw we are getting very less linalool than blanched, this can be attributed by the fact that raw was not exposed to MW while processing while blanched one were exposed to MW during processing and thus volatiles comes out from it. Maximum area is for the blanched sample at 524 watt, 19.371 watt/g for 191 seconds, so maximum loss is from this particular sample than the second. Thus we can conclude that blanching causes loss in volatiles. From this research we have optimized blanching condition for red capsicum and this condition may be used for other vegetables too which will be great advantage in the field of maintaining shelf life of vegetables without much loss of nutrients. Microwave blanching is the method to minimize nutrient loss as compared to steam and water blanching and it is much easier than IR blanching too.

"Lactobacilli belong to the group of Lactic Acid Bacteria (LAB), widely used in the dairy industry nowadays. These bacteria are used as a natural acidifier, for the inoculation of bulk quantities of milk and vegetables, in order to produce a variety of fermented products. As such, large quantities of their biomass are necessary. In addition, during their growth, they naturally produce antimicrobial substances, called bacteriocins. Due to the constantly developing need for natural food preservatives, bacteriocin function and activity has been extensively investigated.
The possibility of producing these substances in mass quantities will be investigated through several techniques. Three carefully selected Lactobacilli, L.plantarum NCIMB 8014, L.casei NCIMB 11970 and L.lactis NCIMB 8586 were grown into simple batch cultures without pH control, where their physicochemical needs were determined. Through the determination of the optimum nutritional conditions for their propagation an optimised growth medium occurred. A simple, liquid turbidometric method was developed to test the bacteriocin productivity of these strains. The antimicrobial activity and potency of the bacteriocins produced, were tested against the target strain L.delbruckii subsp.lactis NCIMB 8117.
The optimised medium was then filtrated via membrane modules of 4 and 30 kDa , in an effort to simplify the medium and facilitate the extraction of the produced substance. The medium’s efficiency in supporting the growth and the bacteriocin production of the bacilli was tested and comparative studies between filtrated and unfiltrated media were done.

Keywords: LAB, Bacteriocins, Target strain, Ultrafiltration, Growth rate, Doubling time"""

The effect of variety and moisture content on some engineering properties of five improved paddy rice varieties was investigated within moisture content range of 10% and 30% dry basis (d.b.). Increase in moisture content was found to increase the linear dimensions, mass of 100 seeds, surface area, apparent volume, true volume, arithmetic mean diameter, effective geometric diameter, sphericity, angle of repose, porosity and static coefficient of friction while bulk density and true density decreased with increase in moisture content. Static coefficient of friction was found to increase as moisture content increased from 0.34–0.46, 0.35–0.59, 0.36–0.46 and 0.34–0.45, respectively on plywood, galvanized steel, mild steel and glass structural surfaces. The highest static coefficient was found on galvanized steel. Angle of repose was found to increase as moisture content increases. The study concludes that variety and changes in moisture content significantly (P < 0.05) affected most of the engineering properties determined.

"Two experimental relations about the effect of the homogenizing pressure P, one on the average fat globule diameter dvs [i.e.  0.6 • log10(P) = C1 - log10(dVS)], and the other on the sedimentation parameter H [i.e.  1.2 • P = C2 - log10(H)], presented in Walstra et al (2006, p. 285), together with Stokes’ Law  v ~ (dvs)^2, lead to a series of practical rules on how to change the homogenizing pressure P in order to increase the creaming time t, to reduce the average fat globule diameter dvs, to reduce the % fat q creamed each day, to reduce the sedimentation parameter H, to increase the total surface area A of all fat globules, and to reduce the fat globule creaming velocity v.
Also a rule is present about the effect of the homogenizing pressure P on the product temperature T. 
For a particular homogenizer, and a particular milk fat content (fat % ≤ 20 mass%), these rules are:
  1)  P-new = P-old * (t-new / t-old)^0.8333;
  2)  t-new  = t-old * (P-new / P-old)^1.2;
  3)  P-new = P-old * (d-vs,old / d-vs,new)^1.6667;
  4)  d-vs,new = d-vs,old * (P-old / P-new)^0.6;
  5)  P-new = P-old * (q-old / q-new)^0.8333;
  6)  q-new = q-old * (P-old / P-new)^1.2;
  7)  P-new = P-old * (H-old / H-new)^0.8333;
  8)  H-new = H-old * (P-old / P-new)^1.2;
  9)  P-new = P-old * (A-new / A-old)^1.6667;
10)  A-new = A-old * (P-new / P-old)^0.6;
11)  P-new = P-old * (v-old / v-new)^0.8333;
12)  v-new = v-old * (P-old / P-new)^1.2;
13)  ΔT = 0.025 * P;
14)  T-new = T-before + 0.025 * P;
This Excel spreadsheet HOMCALC 2.0.xls enables rapid calculations with each of the equations above, and this file includes worked examples on each of the “rules”.
A Help-file at the end of this document explains the theoretical basis of all equations.
"

The scale of pitting activity at the Early Bronze site Fidvár bei Vráble (Southwest Slovakia) is remarkable. Geomagnetic prospection and aerial photography revealed extended areas with clusters of oval negative features both inside the inhabited area and on its perimeter. Excavation trenches in several locations exposed large pits with bell-shaped cross-sections. Numerous ancient sources, ethnographic and ethnohistorical accounts describe the use of such pits as grain storage facilities. Until recently, identical storage installations were common in many parts of the world, for example in Africa, South America, the eastern Mediterranean, and the Middle East. Ethnography and experimental replication demonstrate that their shape was specifically designed to minimize spoilage and loss of grain. This paper presents a preliminary study of the chronology, stratigraphy, relation to domestic structures, distribution, numbers, and capacity of the bell-shaped storage pits at Vráble and addresses the social and political implications of the storage practices at this site. Does large-scale subterranean storage in specialized facilities imply that grain production regularly exceeded subsistence needs, providing surplus grain for trade, exchange, or feasting? Was storage of surplus a communal or a household activity? Why were subterranean storage facilities so ubiquitous? The preference for concealed facilities may imply the need for removing surplus food from circulation or general insecurity, as opposed to large and conspicuous above-ground granaries signalling centralized control and socially acceptable demonstration of wealth.