DARKENING OF BRINED OLIVES BY RAPID ALKALINE OXIDATION

Alkaline oxidation of olives called Californian process is a recommended method of the International Olive Oil Council that generally uses three to five lye treatments. The present investigation was carried out to reduce the number of lye treatments to one and consequently minimize the process duration to about 24 h, preventing the health hazards and environmental pollution. Results revealed that no significant differences were noted between the two cultivars used in this study (Gordal and Ladoelia) in response to ferrous gluconate concentration. Ferrous gluconate (0.4%) should be added during the fixation to stabilize the color produced during air injection. Optimum fixation time was 8 and 12 h for Ladoelia and Gordal cultivars, respectively. When the oxidized black olives were stored in hermetically sealed containers for 4 months in slight brine at different pH values, results revealed that pH 5 was more suitable for maintaining color intensity and firmness of the olives.

PRACTICAL APPLICATIONS

The black oxidizing or Californian processing is one of the three main methods of preparing table olives. In the traditional Californian process, three to five lye treatments are generally used, and when applying this technique on some cultivars stored in brine for more than 6 months, the color cannot be stained enough and fruit firmness becomes softer. Moreover, the duration of the process is long (72–80 h) and the final product is easy to deteriorate. The main goal of this investigation was to modify the Californian process to minimize processing period and improve quality attributes of the obtained olives by using oxidation with one-lye treatment. The results obtained from this study could help table olive industries to design new processes or change the already existing ones in order to improve product quality and make it more competitive in the international market.     

ABSORPTION AND DESORPTION TO AND FROM LIQUID FILMS ON INCLINED PLANES

Two published theoretical models are examined and applied to experimental results for absorption and desorption. The system used was CO₂/H₂O and studies were made for liquid film flow down inclined planes. Experimental results give “Reduced” values of mass ransfer rates.

Interferometric studies give interfacial concentration, penetration and film depths, and take-up of carbon dioxide. In the case of desorption the interferograms are distorted by “deflections.”

All the experimental values for absorption and desorption differ from those calculated from theoretical models.

Desorption is not a mirror image of absorption, and it is approximately 75% of the transfer rate of absorption over a wide operating range.

A comparison is made of the behaviour of static pools and flowing liquid films.     

Three Centuries of Polycyclic Aromatic Hydrocarbons and Teriterpane Records In Tebrau Strait,Malaysia; Recent Pollution Concern in a Pristine Marine Environment

In the last century, application of fossil fuel as the primary source of energy caused environmental pollution in many countries including Malaysia. Polycyclic Aromatic Hydrocarbons (PAHs) are an important class of petroleum contamination. Two sediment cores were collected from the Tebrau Strait at the southern part of Peninsular Malaysia near the border line to Singapore, where entering into the South China Sea. The samples were sliced in certain intervals, extracted with Dichloromethane in Soxhlet apparatus, cleaned and fractionated in 2-steps column chromatography, and analyzed in Gas Chromatography – Mass Spectrometry. The results showed that PAHs input were started soon after World War II and exponentially increased from 1980 onward by 310 ng/g d. w., in comparison it was negligible and probably nature derived during 18^th and 19^th century. The application of compound-specific ratios and pentacyclic teriterpanes suggested the vicinity of sources that atmospherically transported to the sampling locations. They were originated from combusted oil of Southeast Asian and the Middle East, polluting urban sediment and street dusts prior to final deposition. Biomass burning appeared historically as a predominant minor background pollution of both cores. Remarkably, crankcase oil was not traced in this study while it was reported as a predominant source in Malaysia. This study suggested ocean-going ships and Singapore International Airport as the main sources of petroleum pollution in recent decades since there was insignificant rural development surrounding the studied area.     

Application of a modified quasilinearization technique to totally singular optimal control problems†

This paper presents an algorithm for the computation of totally singular optimal control problems. The algorithm is an extension of a modified quasilinearization technique which was originally developed for the solution of non-linear two-point boundary-value problems. A numerical example is included for illustration.     

CHEMOMETRIC CHARACTERIZATION OF FIVE TUNISIAN VARIETALS OF OLEA EUROPAEA L. OLIVE FRUIT ACCORDING TO DIFFERENT MATURATION INDICES

The usefulness of some chemical parameters as a tool to discriminate five varietals of olives was evaluated. Fruits were collected from the same orchard in order to eliminate geographical and climatic effects. Biochemical and quality characteristics in the fruits at complete ripeness were also investigated. Results showed that pomological characteristics and fatty acid composition may differ, depending on the variety and ripeness state, which is confirmed by an analysis of variance. A linear trend between mannitol and oil content was observed ( r =  0.665; P <  0.001). Jeddaria Chaal olive oil had both the highest triolein (39.33%) and oleic acid value (74.43%). However, Chemlali Chouamekh olive oil showed the highest pigment (59.29 and 26.37 mg/kg of chlorophylls and carotenes, respectively) and α-tocopherol content (201.40 mg/kg). Thus, the cultivars were clearly differentiated in their metabolic behavior and the biochemical characteristics of their oils. Ripening state is used mainly as a guideline to establish the olive harvest time. The present data provide information about the maturation patterns of different cultivars and how it can influence the quality of the final product.

PRACTICAL APPLICATIONS

This research is strongly oriented to the agronomic application. The obtained results can orient an agronomist to the optimum ripening date of olive fruits with a good amount of oil and a balanced fatty acid composition.     

Improving the textural properties of Egyptian kariesh cheese by addition of hydrocolloids

In this study, the effect of addition of hydrocolloids (commercial pectin, citrus pectin or carboxymethylcellulose) to Egyptian Kariesh cheese at 0.2, 0.4 and 0.6% (w/w) on chemical composition, yield, rheological and sensory characteristics was investigated. The results revealed that the addition of hydrocolloids increased moisture content and yield values of Kariesh cheeses compared with control. Protein, salt and ash content decreased with increasing hydrocolloids levels. Rheological characteristics (hardness, adhesiveness, springiness, cohesiveness, gumminess, chewiness, resilience) were significantly lower in cheeses made with hydrocolloids. Kariesh cheese made with 0.4% w/w commercial pectin and 0.6% w/w carboxymethylcellulose recorded the highest scores for sensory attributes.     

Chemical Changes After Irradiation and Post-Irradiation Storage in Tilapia and Spanish Mackerel

Influence of gamma irradiation (1.5–10 kGy) and post-irradiation storage up to 20 days at 2 ± 2°C on some chemical criteria of tilapia and Spanish mackerel were studied. Total volatile basic nitrogen formation was lower in irradiated fish than in the unirradiated. Irradiation also caused a larger increase in thiobarbituric acid values which continued gradually during storage. Some fatty acids decreased by irradiation treatments at all doses. Thiamin loss was more severe at higher doses (≥4.5 kGy), whereas riboflavin was not affected. Alpha and gamma tocopherols of tilapia and alpha, beta, gamma, and delta tocopherols, in Spanish mackerel, decreased with increased dose and continued to decrease during 20-day post-irradiation storage.