Food Chemistry 191 (2016) 2–6 Contents lists available at ScienceDirect Food Chemistry journal homepage: www.elsevier.com/locate/foodchem Determination of some minerals and b-carotene contents in aromatic indica rice (Oryza sativa L.) germplasm ⇑ N. Renuka, Sarika V. Mathure, Rahul L. Zanan, Ratnakar J. Thengane, Altafhusain B. Nadaf Department of Botany, Savitribai Phule Pune University, Pune 411007, India article info abstract Article history: 39 aromatic indica rice (Oryza sativa L.) cultivars were characterized for Iron, Zinc, Calcium, Magnesium, Received 4 December 2014 Copper and b-carotene contents. The b-carotene contents were ranging from 1.23 to 9.9 lg/g in brown Received in revised form 2 May 2015 and 0.08 to 1.99 lg/g in milled rice. Among the mineral contents, Magnesium was found ranging from Accepted 11 May 2015 855 lg/g (Gham) to maximum of 1636 lg/g (Badshahbhog) followed by Iron in 32 lg/g (Jirga) to Available online 19 May 2015 218 lg/g (Kalsal), Copper content from 2 lg/g (Girga) to 1004 lg/g (Gham), Zinc content from 25 (Gham) to 165 lg/g (Ambemohar-157) and Calcium ranged from 14 lg/g (Ambemohar pandhara) to Keywords: 67 lg/g (Kate chinoor). The study showed that the germplasm assessed is a good source of micronutrients b-Carotene and can be further exploited in breeding programme. Minerals Aromatic rice landraces Ó 2015 Elsevier Ltd. All rights reserved. Oryza sativa L. spp. indica 1. Introduction conventional or genetic engineering to accumulate micronutrients in edible portion (Stein, 2010). Choice of potential food fortification Rice (Oryza sativa L.) is the staple food of over half the world’s vehicles depends on food commonly consumed by the target population. It is the predominant dietary energy source for 17 group, its affordability and availability (Latfi, Venkatesh Mannar, countries in Asia and the Pacific, 9 countries in North and South Merx, & Heuvel, 1996). Identification of genetic resources with America and 8 countries in Africa. Rice provides 20% of the world’s high levels of targeted micronutrients is a necessary step to dietary energy supply (Donald, 2002). Rice is low in fat and high in enhance micronutrient levels through conventional plant starchy carbohydrate, packed full of vitamins and minerals and breeding (Graham, Senadhira, Beebe, Iglesias, & Monasterio, provides an excellent source of vitamin E, B vitamins (thiamin, 1999; Ortiz-Monasterio et al., 2007). niacin) and Potassium. Dietary minerals and trace elements play Micronutrient concentrations in rice are not sufficient to meet a significant role in maintenance of optimal health. These minerals the recommended daily dietary allowances to sustain good health. and vitamins are limiting in diets (McGloughlin, 2010) and its Milled rice is deficient in many essential micronutrients like Fe, Zn, ingestion in inadequate amount or due to poor bioavailability has vitamin E and vitamin A (Tan et al., 2005; Vasconcelos et al., 2003). negative impacts on the health (Stein, 2010). Main source of all To develop micronutrient enriched staple foods, traditional plant nutrients for people comes from agricultural products (Welch & breeding methods or biotechnological techniques were adopted Graham, 2004). According to Grusak and Cakmak (2005), average by researchers (Bouis, 2000) to combat micronutrient malnutrition mineral requirement from plant food source to human is as fol- (Graham, Welch, & Bouis, 2001). The most effective approach for lows: Calcium (Ca) (12 mg/g food), Copper (Cu) (0.015–0.03 mg/g solving the problem of mineral nutrient deficiencies in humans is food), Iron (Fe) (0.15 mg/g food), Magnesium (Mg) (3.5 mg/g food) to develop rice cultivars with abundant mineral nutrients. Many and Zinc (Zn) (0.15 mg/g food). Deficiencies of these have negative attempts have been made to enhance mineral and b-carotene impact on public health at regional as well as at global level (BC) content through transgenic approaches. However the regula- (Stein, 2010). tory measures have still not allowed these transgenics for commer- Malnutrition and hidden hunger due to deficiency of micronu- cial cultivation (Ramjoue, 2008). The elite landrace in terms of trients is becoming a severe problem in the world, especially in better minerals and BC contents can serve as a promising source developing countries (Datta et al., 2006). One of the interventions as an alternative for GMOs. India is considered as one of the centers against micronutrient malnutrition is breeding of crops through of origin of rice (O. sativa L. ssp. indica) and has also remained as a center of its diversity (Khush, 2000). Our earlier studies on aro- matic rice cultivars from Maharashtra reveled that these cultivars ⇑ Corresponding author. possess superior agronomic traits (Mathure et al., 2011) and have E-mail address: [email protected] (A.B. Nadaf). http://dx.doi.org/10.1016/j.foodchem.2015.05.045 0308-8146/Ó 2015 Elsevier Ltd. All rights reserved. N. Renuka et al. / Food Chemistry 191 (2016) 2–6 3 2. Material and methods 2.1. Rice samples 39 rice cultivars representing 33 non basmati aromatic, 3 bas- mati (long grain 6.61–7.5 mm, 2 mm breadth, length-to-width ratio over 3.0) and 3 non aromatic were selected for the study. These rice cultivars were previously collected by us during 2007 to 2012 and stored at the Department of Botany, Savitribai Phule Pune University, Pune, Maharashtra, India. The seedlings of these cultivars were raised in the experimental field at Karjat rice research station, Karjat, District Raigadh, Maharashtra state, India following routine practice. At maturity the panicles were har- vested, dried in shade, threshed and seeds were used for analyses. 2.2. Quantification of BC and mineral contents BC content in brown and milled rice cultivars were estimated using approved AACC protocol described by Santra, Rao, and Tamhankar (2003). The brown and milled rice grain samples were ground to fine powder and sieved through 100 mesh size sieve. A homogenous suspension was prepared by dispersing 1 g powdered sample in 5 ml water saturated n-butanol, mixed gently and allowed to stand in dark for overnight at room temperature. The samples were centrifuged at 10,000 rpm for 10 min (Eppendorf-5418R, Germany) to obtain the supernatant. The optical density of the supernatant was measured at 440 nm using the UV–visible spec- trophotometer (Shimadzu-1601, Japan) against water saturated n-butanol as blank. A calibration curve was developed using stan- dard BC (Sigma, Bangalore, India) and BC content was estimated. Elements Ca, Cu, Fe, Mg and Zn were estimated following the method of Bhargava and Raghupathi (1993) using diacid mixture method. In 1 g powdered unpolished rice sample, 10 ml HNO3:HClO4 acid mixture (9:4) was added and mixed by swirling. Fig. 1. Heat map representation of nutrient contents in rice grains of aromatic rice The mixture was placed in a digestion chamber and heated at cultivars. higher temperature until fuming of red nitrogen dioxide ceased. The contents were evaporated to reduce the volume to 3–5 ml. The completion of digestion was confirmed by the formation of colorless liquid. After cooling, 20 ml of de-ionized water was added market potential owing to aroma contents (Mathure, Wakte, and the solution was filtered through Whatman filter paper 1. The Nadaf, & Jawali, 2011). These cultivars also exhibited high genetic aliquots of this solution were used for determination of mineral diversity (Mathure, Nadaf, & Jawali, 2010). As these cultivars elements. Individual standard stock solutions (1 mg/L) for each have potential to effectively contribute towards the gene pool, a mineral element were prepared for quantification. Different set of 39 aromatic rice cultivars was characterized for minerals dilutions ranging from low to high concentrations were made and BC contents. and standard graph was plotted. The mineral contents were Fig. 2. Distribution of b-carotene content (BC) in brown and milled rice grains of aromatic rice cultivars. 4 N. Renuka et al. / Food Chemistry 191 (2016) 2–6 estimated in triplicate using atomic absorption spectrophotometer 2.3. Data analyses (Perkin-Elmer 3110; Perkin Elmer, Waltham, MA). The operating parameters for working these elements were set as per the The descriptive analysis including mean, standard deviation, manufacturer’s protocol. Four external standard curves were frequencies and minimum and maximum values of variables was constructed using reference standard to quantify the metals performed. Paired t test was conducted to determine significance content in all samples. Calibration curves were performed with between BC and minerals contents using SPSS software (version 5–6 different concentrations. For elemental analyses, a 10 cm 11, Chicago, IL, USA). 1-slot burner head with standard air-acetylene flame and single element hollow cathode lamps were employed. A spoiler nebulizer 3. Results and discussion was applied for all the elements and for the Mg determination impact bead nebulizer was used. IUPAC criteria were followed to The BC content in brown rice (BC brown) and milled rice (BC calculate the detection limit (Long & Winefordner, 1983). milled), Ca, Cu, Fe, Mg and Zn are depicted in Fig. 1 and Fig. 3. Distribution of mineral content in rice grains of aromatic rice cultivars. N. Renuka et al. / Food Chemistry 191 (2016) 2–6 5 Supplementary 1. Maximum BC was recorded in brown rice of The values of Fe, Zn and Mg are in agreement to that of the Belgaum basmati (9.9 lg/g) followed by Girga (9.56 lg/g), earlier reports except Ca (Graham et al. 1999; Itani, Tamaki, Ambemohar (7.87 lg/g) and the least was recorded in Kaligajvili Arai, & Horino, 2002; Heinemann, Fagundes, Pinto, Penteado, & (1.23 lg/g). In majority of the cultivars, BC content in brown rice Lanfer-Marquez, 2005; Shabbir, Anjum, Zahoor, & Nawaz, 2008; was less than 6 lg/g whereas, in milled rice, it varied in a narrow Jiang et al., 2008; Krishnan et al., 2009; Zeng et al., 2004).