Detection, Purity Analysis, and Quality Assurance of Adulterated Peanut (Arachis Hypogaea) Oils

Comparison of near infrared spectroscopy and Raman spectroscopy for the identification and quantification through MCR-ALS and PLS of peanut oil adulterants

Peanut oil is considered one of the best frying oils, and, consequently there is an increasing worldwide demand. This has led to adulteration practices with unhealthy, synthetic or less expensive oils which raises concerns related with public health safety. Therefore, there is a high need for rapid, versatile, low-cost and reliable analytical methods, such as vibrational spectroscopic techniques, capable of identifying and quantifying the respective adulteration. The objective of this work focused on the application of two different vibrational spectroscopic techniques (NIR and Raman spectroscopy) for the qualitative and quantitative analysis of two adulterants in pure peanut oil, namely corn oil and vegetable oil. For the quantitative analysis two chemometric methods, namely PLS and MCR-ALS, were compared while for the qualitative analysis only MCR-ALS was tested. The analysis of peanut oil adulteration was performed by adding each adulterant individually and also by blending the peanut oil with both adulterants simultaneously. A total of 69 samples were analyzed, which was comprised by two sets of 20 samples each containing just one adulterant and another set of 29 samples containing both adulterants. Several pre-processing techniques were tested. The qualitative analysis performed by MCR-ALS allowed the identification of all the adulterants using both NIR and Raman spectra, with correlation coefficients higher than 0.99. For the quantification, none of the chemometric methods as well as the vibrational spectroscopic techniques tested showed significant better results. Nonetheless, the determination coefficients and the relative percentage errors for the validation samples for most of the developed models were higher than 0.98 and lower than 15%, respectively. Concluding, MCR-ALS was capable of correctly extracting the spectral profiles of all the adulterants in very complex mixtures (as the pure spectra of the adulterants and peanut oil are very similar) and both MCR-ALS and PLS were able to quantify the adulteration with low RE. To the best of our knowledge, it was the first time that MCR-ALS was used for the qualitative analysis of peanut oil adulteration (with all adulterants added simultaneously) and MCR-ALS and PLS were compared for the quantification of peanut oil adulteration using both NIR and Raman spectroscopy.

Legume Seeds as an Important Component of Human Diet

Legumes are an important source of nutrients (proteins, carbohydrates, water soluble vitamins, minerals) for human nutrition [...].

Effect of Syzigium aromaticum and Allium sativum spice extract powders on the lipid quality of groundnuts (Arachis hypogaea) pudding during steam cooking

Groundnut seeds (Arachis hypogaea) contain higher concentrations of unsaturated lipids which are prone to oxidation in formulated foods. This study determined the antioxidant activities of water extract powders from two spices (Syzigium aromaticum and Allium sativum) and their ability to preserve the quality of lipids in groundnuts pudding during steam cooking with 0, 0.5, 1, 2 and 4% of spice extract powders. Total phenolic (TPC) and flavonoid (FC) contents of extracts from S. aromaticum were 140.23 mg GAE/100g extract and FC of 110.34 mg CAE/g extract compared to values of Allium sativum extracts (54.28 mg GAE/100g extract and 34.80 mg CAE/g extract). The showed DPPH free radical scavenging activities of the extract from S. aromaticum depending on the concentration ranged from 82.15% to 97.66% and this was higher than the activities of A. sativum but comparable to the values of buthylhydroxytoluene used as control. The chemical analysis of oil extracted revealed that the addition of the spice extract powders limited the appearance of oxidation products characterized by a reduction of up to 9-fold of peroxide value, 5-fold for anisidine and 2-fold for thiobarbituric acid reactive species. In many cases, the addition of S. aromaticum spice extract powder to the pudding better prevented lipid oxidation likely because of its superior ability to scavenge peroxyl radicals (ROO^., HO^., DPPH ^. ). In a nutshell, the addition S. aromaticum and A. sativum spice extract powders on grilled groundnuts paste for groundnuts pudding preparation in household can help preserve its lipid quality.