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The one-third of all food produced for human use is wasted each year which has made food waste a serious problem all around the world. Citrus juice manufacturing factories generate peel leftovers that can account for 50-60% of the weight of the fruit, contributing significantly to food waste. This study investigates the extraction of orange and lemon peel oils using the Soxhlet process and their analysis via gas chromatography. The aim is to identify and quantify key volatile compounds present in these oils, thereby putting the leftover peels to use. Fresh orange and lemon peels were transformed into zest and extracted using Hexane and Ethanol as solvent in a Soxhlet apparatus. Gas chromatography with a specialized column and detector unveiled major volatile compounds, including limonene, linalool, citral. These compounds contribute to the characteristic aroma and potential bioactivity of the oils. Orange peels displayed notably higher limonene content compared to lemon peels. This approach illuminated the chemical composition of the oils, offering opportunities in food, cosmetics, and fragrance industries. Orange peels contained 70-90% limonene, significantly more than lemon peels. The study concluded that peels harbor 28 volatile substances, with limonene responsible for their distinctive citrus scent. In sum, this research underscores the effectiveness of Soxhlet extraction, providing insights into orange and lemon peel oils’ composition using Gas chromatography and applications.

Beta fleck is a troublesome segregation defect in many titanium alloys. It has previously been investigated by several authors and appears to have two formation mechanisms, one similar to that of “freckle” in steels and nickel-base alloys, the other arising in the “crystal rain” effect seen in conventional steel ingots. The freckle defect has been extensively studied and several theories developed to account for its formation in both remelted ingots and directional castings. In this work we compare the findings of investigations into the nickel-base freckle formation mechanism to similar conditions in the vacuum arc remelting of titanium alloys. We find that there are strong similarities between the beta fleck formation conditions and the parameters related to the Rayleigh Number criterion for freckle formation. In particular, the dendritic solidification parameters and the density dependence on segregation coefficients both fit well with the conditions proposed to characterise freckle formation. The second formation mechanism arises in the columnar to equiax transition in solidification. The condition for the avoidance of the defect in the two cases is the shown to be the same, namely the use of a very low VAR melting rate, but that it is unlikely to be 100% successful in preventing defect formation. We propose that the techniques presently in use for alloy development in the superalloy field through optimising the composition for minimum sensitivity to freckle formation should be applied to the formulation of future titanium alloys; also that attention should be paid to developing the PAM process to provide suitable solidification conditions for defect absence in a final ingot.