horticulturae Article Fatty Acid Profile, Tocopherol Content of Seed Oil, and Nutritional Analysis of Seed Cake of Wood Apple (Limonia acidissima L.), an Underutilized Fruit-Yielding Tree Species Shrinivas Lamani 1, Konerira Aiyappa Anu-Appaiah 2, Hosakatte Niranjana Murthy 1,* , Yaser Hassan Dewir 3,* and Hail Z. Rihan 4,5 1 Department of Botany, Karnatak University, Dharwad 580003, India; [email protected] 2 Department of Microbiology and Fermentation Technology, CSIR-CFTRI, Mysuru 570020, India; [email protected] 3 Plant Production Department, College of Food & Agriculture Sciences, King Saud University, Riyadh 11451, Saudi Arabia 4 School of Biological Sciences, Faculty of Science and Environment, University of Plymouth, Drake Circus, Plymouth PL4 8AA, UK; [email protected] 5 Phytome Life Sciences, Launceston PL15 7AB, UK * Correspondence: [email protected] (H.N.M.); [email protected] (Y.H.D.) Citation: Lamani, S.; Anu-Appaiah, Abstract: The present study was aimed at analyzing the fatty acid composition, tocopherols, and K.A.; Murthy, H.N.; Dewir, Y.H.; physico-chemical characterization of wood apple (Limonia acidissima L.) seed oil and the nutritional Rihan, H.Z. Fatty Acid Profile, profile of seed cake. The fatty acids in seed oil were analyzed by gas chromatography–mass spec- Tocopherol Content of Seed Oil, and trometry (GC-MS), and the total seed oil was 32.02 ± 0.08%, comprising oleic (21.56 ± 0.57%), Nutritional Analysis of Seed Cake of alpha-linolenic (16.28 ± 0.29%), and linoleic acid (10.02 ± 0.43%), whereas saturated fatty acid con- Wood Apple (Limonia acidissima L.), tent was 33.38 ± 0.60% including palmitic (17.68 ± 0.65%) and stearic acid (14.15 ± 0.27%). A greater an Underutilized Fruit-Yielding Tree amount of unsaturated fatty acids (52.37%) were noticed compared to saturated fatty acids (33.38%); Species. Horticulturae 2021, 7, 275. hence the seed is highly suitable for nutritional and industrial applications. Gamma-tocopherol was https://doi.org/10.3390/ present in a higher quantity (39.27 ± 0.07 mg/100 g) as compared to alpha (12.64 ± 0.01 mg/100 g) horticulturae7090275 and delta (3.77 ± 0.00 mg/100 g) tocopherols, which are considered as natural antioxidants. The spectrophotometric technique was used for quantitative analysis of total phenolic content, and it Academic Editors: Rosario ± Paolo Mauro, Carlo Nicoletto and revealed 135.42 1.47 mg gallic acid equivalent /100 g DW in seed cake. All the results of the studied Leo Sabatino seed oil and cake showed a good source of natural functional ingredients for several health benefits. Received: 14 August 2021 Keywords: wood apple; fatty acid profile; tocopherol; nutritional; phenolics; GC-MS; HPLC Accepted: 27 August 2021 Published: 1 September 2021 Publisher’s Note: MDPI stays neutral 1. Introduction with regard to jurisdictional claims in Plant seeds are an important source of oils and fats to meet nutritional, industrial, and published maps and institutional affil- pharmaceutical needs [1]. Oils and fats are composed of neutral lipids, majorly triglycerides, iations. which are the sources of nutraceutical compounds that are an essential part of the human diet and major constituents for the storage of energy, structural and functional composition of cells [2]. Seed oil is used for the preparation of soap and detergents, cosmetics, and also used as ingredients for paint and varnishes, lubricants, and organic pesticides [3]. Oils Copyright: © 2021 by the authors. rich in polyunsaturated fats have been related to the prevention of coronary heart diseases, Licensee MDPI, Basel, Switzerland. diabetes, cancer, and depression, whereas cholesterol and saturated fats cause chronic This article is an open access article diseases [4]. Many seed oils are reported to contain tocopherols, and they are considered as distributed under the terms and effective fat-soluble antioxidants present in the oil, which helps to protect cell membranes, conditions of the Creative Commons improvement in blood circulation, and treating various diseases [5]. Most seeds and Attribution (CC BY) license (https:// vegetable oils, such as groundnut, sunflower, soybean, and peanut, are the most important creativecommons.org/licenses/by/ oil sources for cooking, canning, and preparations of emulsions and margarine [4]. 4.0/). Horticulturae 2021, 7, 275. https://doi.org/10.3390/horticulturae7090275 https://www.mdpi.com/journal/horticulturae Horticulturae 2021, 7, 275 2 of 12 Horticulturae 2021, 7, x FOR PEER REVIEW 2 of 13 are theThe most increasing important population oil sources for of thecooking, world canning, is creating and preparations a shortage of of food emulsions sources which andpermits margarine the interest [4]. toward underutilized fruits. Seed oil and cake is the major portion of theThe human increasing diet populati due toon abundant of the world nutrients, is creating protection a shortage from of food oxidative sources stress,which and sev- permitseral diseases. the interest Seeds toward have underutilized beengiven specialfruits. Seed attention oil and throughout cake is the major theworld, portionparticularly of the human diet due to abundant nutrients, protection from oxidative stress, and several underutilized fruits. As a biodiversity country, India has been a habitat for thousands of diseases. Seeds have beengiven special attention throughout the world, particularly un- wild underutilized fruit seeds, which could be exploited directly as foods or used to obtain derutilized fruits. As a biodiversity country, India has been a habitat for thousands of wild underutilizedvaluable natural fruit compoundsseeds, which andcould derivatives be exploited [6 ].directly as foods or used to obtain valuableWood natural apple compounds (Limonia acidissimaand derivativesL.) is [6]. an underutilized fruit-yielding tree species native to IndiaWood and apple Sri (Limonia Lanka acidissima (Figure1 L.)A). is Woodan underutilized apple (Figure fruit-yielding1B) is used tree species by the na- tribal and tiverural to India population and Sri Lanka of the (Figure developing 1A). Wood world, apple which (Figure contributes 1B) is used toby thethe tribal traditional and health ruralsystem population [6]. Extracts of the ofdevelo woodping apple world, are which used contributes traditionally to the for traditional curing various health diseases, sys- such temasantimicrobial, [6]. Extracts of wood antifungal, apple are liver, used and trad cardiacitionally tonic, for curing dysentery, various hiccough, diseases, such sore as throat, and antimicrobial,is a good antidote antifungal, for snakebite liver, and andcardiac used tonic, as a dysentery, face cream hiccough, to remove sore small throat, spots and andis lesions aon good the antidote skin. The for phytochemical snakebite and used analysis as a face of L. cream acidissima to removeplant small parts spots showed and lesions the presence of onalkaloids, the skin. flavonoids,The phytochemical phenols, analysis terpenoids, of L. acidissima tannins, plant fats, sterols,parts showed saponins, the presence glycosides, gum, ofmucilage, alkaloids, and flavonoids, fixed oils phenol [7,8].s, Theterpenoids, small, numerous,tannins, fats, and sterols, white saponins, seeds scattered glycosides, throughout gum, mucilage, and fixed oils [7,8]. The small, numerous, and white seeds scattered fruits(Figure1C) showed an abundance in protein, carbohydrate, amino acid content and throughout fruits(Figure 1C) showed an abundance in protein, carbohydrate, amino acid contenthigh amount and high of amount iron (Fe), of iron zinc (Fe), (Zn), zinc sodium (Zn), sodium (Na), potassium(Na), potassium (K), (K), phosphorus phosphorus (P), copper (P),(Cu), copper magnesium (Cu), magnesium (Mg) and (Mg) manganese and manganese (Mn) [ 9(Mn)]. However, [9]. However, no detailed no detailed reports reports are available areon available wood apple on wood seed apple oil (Figure seed oil1 D).(Figure Therefore, 1D). Therefore, the present the present study study was aimedwas aimed atanalyzing atanalyzingthe fatty acid the fatty composition acid composition by GC-MS, by GC-MS, tocopherols tocopherols by HPLC/FD, by HPLC/FD, and and physico-chemical physico- chemicalproperties properties of seed of oil, seed and oil, nutritional and nutritional analysis analysis of wood of wood apple apple seed seed cake. cake. FigureFigure 1. 1.WoodWood apple apple (Limonia (Limonia acidissima acidissima L.)-TreeL.)-Tree (A), Fruit (A), ( FruitB), Seeds (B), (C Seeds), and ( OilC), ( andD). Oil (D). 2.2. Materials Materials and and Methods Methods 2.1.2.1. Samples Samples Ripened fruits of Limonia acidissima L. were collected from Itagi, Koppal District, Karnataka, India, during February 2019. The collected fruits were washed under running tap water to remove the pulp content. Seeds were dried in a hot air oven at 48 ± 2 ◦C to remove moisture and stored at −20 ◦C until future analysis. Horticulturae 2021, 7, 275 3 of 12 2.2. Standards and Chemicals n-Hexane, methanol, potassium hydroxide (KOH), hydrochloric acid, 14% methanolic boron trifluoride (w/v), helium, 5% ethanolic pyrogallol (w/v), diethyl ether, ethanol, milli-Q-water, acetone, phenolphthalein, chloroform, Hanus iodine solution, potassium iodide, sodium thiosulfate, sodium hydroxide, phosphate-buffered saline, bovine serum albumin, copper sulfate, Folin-Ciocalteu’s reagent, anthrone reagent, and sodium carbonate were of analytical grade from Merck, Bangalore (India). Glucose, gallic acid, α, γ, and δ-tocopherols were purchased