Skip to main content
ARS Home » Southeast Area » Dawson, Georgia » National Peanut Research Laboratory » Research » Publications at this Location » Publication #294327

Title: Capacitance Sensor For Nondestructive Determination Of Total Oil Content In Nuts

item Kandala, Chari
item RACHAPUTI, R - Queensland Department Of Primary Industries & Fisheries

Submitted to: Journal of Sensor Technology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 7/2/2013
Publication Date: 9/7/2013
Citation: Kandala, C., Rachaputi, R.C. 2013. Capacitance Sensor For Nondestructive Determination Of Total Oil Content In Nuts. Journal of Sensor Technology. 3:42-46.

Interpretive Summary: The peanut plant is a small annual herb, belonging to the family of fabaceae of the genus arachis and botanically named as arachis hypogaea. Some common names are groundnut, earthnuts etc. Types of peanuts containing high oil are suitable for extracting oil from them for cooking, as well as for bio-diesel production. Peanut types containing low oil are used in making peanut containing snack foods. peanut oil obtained from certain types was found to have a high amount of oleic acid. Consumption of oleic acid is believed to be beneficial to human health by reducing low-density lipoproteins (LDL) while maintaining high-density lipoprotein (HDL), that slows down occurrence of atherosclerosis, and may reverse the inhibitory effect of insulin production. Thus knowing the TOC in the peanut varieties would be useful in estimating the amount of oleic acid in them. Presently, chemical methods such as using a Soxhlet instrument for extracting oil content from a known weight of peanuts, and from it calculating the TOC of the sample are used. These methods are time consuming and destructive. Presently there are no commercial meters that would measure the TOC of peanut kernels rapidly and nondestructively. Peanuts have to be shelled and cleaned before MC is measured. In this work the design and working of a low-cost meter that can quickly and nondestructively estimate the TOC in a single peanut is described. A commercial instrument that can be developed on these lines would be very useful for peanut breeders in all peanut growing countries around the world.

Technical Abstract: Earlier a simple, low cost instrument was designed and assembled in our laboratory, that could estimate the moisture content (MC) of in-shell peanuts (MC range 9% to 20%) and yellow-dent field corn (MC range 7% to 18%). In this method a sample of of in-shell peanuts or corn was placed between a set of parallel plate electrodes and the impedance (z) and phase angle (q) of the system were measured at 1MHz and 5 MHz. Using the measured z and q values, the computed capacitance C, and the MC values obtained by standard methods, semi-empirical equations were developed to estimate the moisture content in peanuts. In this work similar equations were developed, using the measurements at an additional frequency of 9 MHz, to predict the total oil content (TOC) in single shelled peanuts, picked from each of the several types cultivated by the breeder’s. Knowing the TOC of the different breeds would help the breeders to determine the suitability of the varieties for large scale plantation.