MICROWAVE-ASSISTED EXTRACTION OF CAPSAICINOIDS FROM CAPSICUM FRUIT

The applicability of microwave irradiation to assist the extraction of capsaicinoids from capsicum fruit was investigated. The procedure involved irradiation of 2 g samples in a closed-vessel followed by gas chromatography of capsaicinoid derivatives. The optimum conditions for extraction were determined to be acetone at 30% power for 7 min irrespective of ground or whole tissue.
The yield of the compounds extracted was significantly greater (P < 0.05) using microwave-assisted extraction (MAE) compared to traditional reflux and shaken flask methods. A single extraction step was efficient in recovering approximately 95% of the total capsaicinoid fraction in 15 min compared with 2 h for the reflux and 24 h for the shaken flask methods. Due to the considerable savings in time and energy as well as reliability, this technique is suitable for fast extraction of capsaicinoids from large samples.     

δ state controllability by admissible controls for linear time-invariant systems

The necessary and sufficient conditions for a linear time-invariant continuous system to be δ state controllable by admissible controls are developed. The corresponding conditions for a linear time-invariant discrete system are stated without proof.     

EFFECT OF VARIOUS ANTIOXIDANTS ON THE OXIDATIVE STABILITY OF ACID AND ALKALI SOLUBILIZED MUSCLE PROTEIN ISOLATES

Protein isolates prepared from cod ( Gadus morhua ) myofibrillar proteins using acid or alkali solubilization are susceptible to oxidative rancidity. Oxidation could be delayed by the exogenous addition of antioxidants. The objective of this research was to compare the efficacy of antioxidants such as δ-tocopherol, butylated hydroxyanisole (BHA) and propyl gallate, to inhibit oxidation in acid- and alkali- solubilized cod protein isolates. Oxidation was catalyzed using cod hemolysate. Oxidation of lipids was monitored by the measurement of thiobarbituric acid reactive substances and painty odor. Results showed that protein isolates prepared using the acid process was significantly ( P <  0.05) more susceptible to lipid oxidation than alkali-solubilized protein isolates. Regardless of pH treatments, the efficacy of various antioxidants decreased in the order propyl gallate  >  BHA  >  δ-tocopherol.

PRACTICAL APPLICATIONS

Research has shown that seafood available for human consumption is rapidly getting depleted and that many fish species may become extinct in the next half-century or so. Acid and alkali solubilization methods are recent but well-known techniques used for preparing protein isolates from under-utilized aquatic species and the by-products of seafood industry. Although numerous researchers have studied the use of acid and alkali processes on several sources of seafood, almost no research has been done on the use of antioxidants to protect protein isolates from lipid oxidation. In our research, we have studied the effect of various antioxidants on the oxidative stability of acid- and alkali-solubilized fish myofibrillar proteins. The results from this work will enable the seafood industry to properly identify the process and the type of antioxidants required for making muscle food products with increased oxidative stability.     

MODELING the POWER CONSUMPTION DURING SHEETING of DOUGHS FOR TRADITIONAL INDIAN FOODS

The model given by Levine has been extended to account for the effects of moisture, salt and fat through appropriate modifications based on theory and computational experience. Appropriate modifications to consistency index and flow behavior index as a function of moisture, salt and fat are given. the thickness of sheeted dough has been modeled as a function of gap, reduction ratio and the flow behavior index which constitutes an important contribution. the model so modified was fitted to experimental data on power consumption in sheeting dough prepared from two flour types, viz., whole wheat flour and resultant atta, respectively, at five combinations of gap and reduction ratios and three levels each of moisture, salt and fat (conforming to actual use ranges) using Nelder-Mead algorithm for nonlinear optimization. These models provided 12 constants for each flour type which gave fundamental information on the dough properties for each flour type. Three-dimensional graphics have been used to interpret the model. These models appear to be of much practical use.     

Thermodynamic Stabilities of Lanthanum Tungstates Using a Calcium Fluoride Solid Electrolyte Galvanic Cell

Abstract

A knowledge of the thermodynamic stabilities of the lanthanum tungstates measured as the Gibbs energies of formation from the free oxides is important as lanthanum is used as a powerful desulphurizing agent and tungsten as a special alloying element in the production of clean steels and special steels. These data will also be useful as the system La₂O₃ WO₃ can be a model since it exhibits many compounds between the end members. Excepting one EMF work, no information is available in the literature on the thermodynamics of this system. This system exhibits the compounds 5 La₂O₃·22 WO₃, La₂ O₃ · 3 WO₃, La₂O · 2 WO₃, 7 La₂O₃ · 8 WO₃,La₂O · WO₃, 3 La₂O₃ · 2 WO₃ and 5 La₂O₃ · 2 WO₃. The compounds were prepared from reagent grade free oxides by solid state sintering at high temperature followed by X-ray diffraction. The standard Gibbs energies of formation of the compounds from the free oxides were determined by operating the following galvanic cells with calcium fluoride as solid electrolyte.

O₂(g), Pt/ La₂O₃ · LaOF// CaF₂/ / 5 La₂O₃ · 22 WO₃, WO₃, LaOF/Pt, O₂(g)

O₂(g), Pt/La₂O₃ · LaOF//CaF₂//5 La₂O₃ · 22 WO₃, La₂O₃ · 3 WO₃, LaOF/Pt, O₂(g)

O₂(g), Pt/La₂O₃ · LaOF//CaF₂// La₂O₃ · 3 WO₃, La₂O₃ · 2 WO₃ LaOF/Pt, O₂(g)

O₂(g), Pt/La₂O₃ · LaOF//CaF₂// La₂O₃ · 2 WO₃, 7 La₂O₃ · 8 WO₃, LaOF/Pt, O₂(g)

O₂(g), Pt/La₂O₃ · LaOF//CaF₂//La₂O₃ · WO₃, 3La₂O₃ · 2 WO₃ LaOF/Pt, O₂(g)

O₂(g), Pt/La₂O₃ · LaOF//CaF₂//3 La₂O₃ · 2 WO₃, 5La₂O₃ · 2 WO₃ LaOF/Pt, O₂(g)

O₂(g), Pt/ La₂O₃ LaOF// CaF₂/ / 3 La₂O₃2 WO₃, La₂O₃, 2 WO₃ LaOF/Pt, O₂(g)

Stable, reproducible EMFs were obtained in the temperature range 1123 to 1273 K. The net cell reactions are respectively as follows:

5 La₂O₃ + 22 WO₃ = 5 La₂O₃ · 22 WO₃

7 La₂O₃ + 3 (5 La₂O₃ · 22 WO₃) = 22 (La₂O₃ · 3 WO₃)

La₂O₃ + 2 (La₂O₃ · 3 WO₃) = 3 (La₂O₃ · 2 WO₃)

3 La₂O₃ + 4 (La₂O₃) = 7 La₂O₃ · 8 WO₃

La₂O₃ + 7 La₂O₃ · 8 WO₃ = 8 (La₂O₃ · WO₃)

La₂O₃ + 2 (La₂O₃ · WO₃) = 3 La₂O₃ · 2 WO₃

2 La₂O₃ + 3 La₂O₃ · 2 WO₃ = 5 La₂O₃ · 2 WO₃

The standard Gibbs energies of formation of the different lanthanum tungstates are then calculated by appropriately combining from the above cell reactions and their Gibbs energy changes obtained from the experimental EMF data. The present data are discussed in the light of EMF data reported in the literature for WO₃-rich compounds in the system.     

STUDIES ON FLAVOR CHANGES DURING DRYING OF DILL (Anethum sowa Roxb.) LEAVES

Indian dill (Anethum sowa Roxb.) is a popular herb widely used in culinary preparations and is characterized by a persistent cineolic flavor. To study the flavor quality of the fresh and dried herb, it was subjected to through-flow, cross-flow, vacuum and freeze drying procedures. The volatile oils obtained from the fresh and dried samples were examined by gas chromatography and gas chromatography-mass spectrometry and the changes in their flavor compositions determined. Seventeen compounds have been identified in Indian dill leaf oil, of which β-cubebene is being reported for the first time. The proximate composition of the dried herb is also reported.