Peanut is one of the major source of edible oil and protein content available for human consumption and is consumed worldwide. The freshness and quality of peanut are the major concerns in the food markets as in storage, it is most likely to undergo either surface contamination or a change in internal quality in terms of oil and flavor by gaining moisture and oxygen from the atmosphere. A peanut is considered to be of good quality if it have a moisture content in range of 5–7 %, protein (25–30 %), and an oil content (45–55 %) (Bilal et al. 2020; Raigar and Mishra 2016). Moreover, peanuts are rich in fiber, folate, vitamin E, magnesium and phenolic compounds which is beneficial for human health (Mora-Escobedo et al. 2015). The nutritional and sensory acceptability of peanut is mostly dependent on moisture and oil content (Free fatty acid, Peroxide value). In addition, peanuts may gain excess oxygen content which leads to rancid flavor while if they gain excess moisture, it will promote microbial growth on the surface of the peanut which thereby change the color of the peanuts. The majority of physico-chemical AOAC methods for determination of quality characteristics of peanut are time consuming, slow and fatal (Mishra et al. 2018). Thus, there is a missing piece or pieces in the research literature that has not yet been explored regarding a technique that somewhat allows rapid testing of peanut quality.
Some of non-destructive and rapid testing methods are rapidly popularized in the current food scenario out of which the Fourier transform near infrared spectroscopy (FTNIR) is an advanced instrumental method, which may be used for the rapid determination of nutrients and characterization of food products. FTNIR offers many unique benefits such as non-destructive nature, economical, environment friendly, shorter time intake, and no additional sample preparation. Chemometric approaches (partial least square) are commonly used to analyze the data obtained from FTNIR for correlations of the models (Srivastava et al. 2018b; Nturambirwe et al. 2019).
Latest research has set out the adaptability and potentiality of FTNIR for analysis of the physical and chemical properties of several food samples. Srivastava et al. (2018 b) studied the quality of the rice grain and differentiated the infested rice with good quality rice grain. Moreover, the determination of quality change during the storage of the rice due to insect was also reported in the study. The rapid method for analysis of phytic acid was done for the green gram seeds (Pande and Mishra 2015). Several studies showed the analytical capacity of FTNIR was excellent for essential and nonessential amino acids, fatty acids, and microbial contaminations in cereals and oilseeds (Mishra et al. 2018; Carvalho et al. 2019; Lopes et al. 2020).
Although, FTNIR spectroscopy intermodal with multivariate analysis has been employed to measure the composition in cereals, oilseeds and legumes in term of their moisture, protein and, oil content etc. The intimate relationship between spectroscopic measurement and physical/microbial impurities as surface contamination, and quality of peanut seeds still a research issue. Also, the study attempt on the application of Fourier transform near-infrared spectroscopy (FTNIR) for discrimination of peanut kernel quality characteristics namely infested kernel, surface impurities etc. for peanut with an incrementally rise in storage days. Thus, the objective of this study was to evaluate the chemical and nutritional quality characteristic of peanut samples by using the FTNIR spectroscopy technique with multivariate partial least squares analysis regression (PLSR).