ISSN 1519-6984 (Print) ISSN 1678-4375 (Online) THE INTERNATIONAL JOURNAL ON NEOTROPICAL BIOLOGY THE INTERNATIONAL JOURNAL ON GLOBAL BIODIVERSITY AND ENVIRONMENT Original Article Evaluation of some nutritional quality criteria of seventeen Moroccan dates varieties and clones, fruits of date palm (Phoenix dactylifera L.) Avaliação de alguns critérios de qualidade nutricional de 17 variedades e clones marroquinos de datas, frutos de tamareira (Phoenix dactylifera L.) A. Alahyane*a , H. Harrakb , I. Elateria , J. Ayoura , A. Ait-Oubahouc , M. Benichoua , M. E. Abderrazika a Cadi Ayyad University, Faculty of Sciences-Semlalia, Department of Biology, Laboratory of Agro-Food, Biotechnologies and Valorization of Plant Bioresources, Marrakesh, Morocco. b National Institute of Agricultural Research – INRA, Research Unit of Plants improvement and Quality, Laboratory of Food Technology and Quality, Marrakesh, Morocco. c Hassan II Agronomy and Veterinary Institute, Horticultural Laboratory, Ait Melloul, Morocco. Abstract Date fruit is known to be the staple food in the Arab countries. It provides a lot of potential health benefits and can be the essential source of nutrients. The majority of Moroccan varieties are not characterized for their chemical, biochemical and quality properties. The aim of this work was to assess the chemical composition of 17 varieties of Moroccan date fruits (Phoenix dactylifera L.) and to determine their nutritive components. The analysis showed that the dates are rich in sugars (51.80-87.98%), they contain low concentration of proteins (1.09-2.80%) and lipids (0.16-0.39%). The predominant mineral is potassium (1055.26-1604.10 mg/100 g DW). Moreover, they contain high concentrations of malic acid (69.48-495.58 mg/100 g (DW)), oxalic acid (18.47-233.35 mg/100 g DW) and tartaric acid (115.70-484.168 mg/100 g DW). These results suggest that the date fruit are nutritious and can be an excellent source for human nutrition and health benefits. Keywords: Morocco, Phoenix dactyliferea, date fruits, nutritional quality, organic acids, minerals. Resumo A fruta da tâmara é conhecida por ser o alimento básico nos países árabes. Oferece muitos benefícios potenciais à saúde e pode ser a fonte essencial de nutrientes. A maioria das variedades marroquinas não se caracteriza por suas propriedades químicas, bioquímicas nem de qualidade. O objetivo deste trabalho foi avaliar a composição química de 17 variedades de frutos de tâmara marroquina (Phoenix dactylifera L.) e determinar seu valor nutritivo. A análise mostrou que as tâmaras são ricas em açúcares (51,80-87,98%) e contêm baixa concentração de proteínas (1,09-2,80%) e lipídios (0,16-0,39%). O mineral predominante é o potássio (1.055,26-1.604,10 mg/100 g DW). Além disso, contêm altas concentrações de ácido málico (69,48-495,58 mg/100 g DW), ácido oxálico (18,47-233,35 mg/100 g DW) e ácido tartárico (115,70-484,168 mg/100 g DW). Esses resultados sugerem que o fruto da tamareira é nutritivo e pode ser uma excelente fonte de nutrição humana e conferir benefícios à saúde. Palavras-chave: Morocco, Phoenix dactyliferea, frutos de tamareira, qualidade nutricional, ácidos orgânicos, minerais. 1. Introduction The date palm (Phoenix dactyliferea L.) is one of the minerals (Punia 2016; Benmeddour et al., 2013). It is oldest cultivated trees and the most popular in the hot preferable to consume dates regularly, because of its arid regions (Saleh et al., 2011). Based on Arabic terms beneficial properties in increasing sexual stamina, reducing and accepted universal terminology, the fruit of date sterility, decreasing fatigue and sluggishness in anemic palm cultivars are classified into five stages of ripening patients (Siddiqi et al 2020; Vayalil 2012). viz., Hababouk, Kimri, Khalal, Rutab and Tamar (full ripe Dates are used and consumed during the month of stage) (Baliga et al., 2011). Ramadan by Muslims all over the world to break their Dates are a very good source of numerous nutritive hunger (Umar et al., 2016). It is an important subsistence components, viz., sugars, proteins, fats, dietary fibers, crop in dry and semi dry regions of the world due to its *Corresponding author: [email protected] Received: 14 Apr. 2020 – Accepted: 24 Aug. 2020 This is an Open Access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. Brazilian Journal of Biology, 2022, vol. 82, e236471 | https://doi.org/10.1590/1519-6984.236471 1/12 Alahyane, A. et al., socioeconomic and traditional value (Chandrasekaran and and transported to the food science laboratory under the Bahkali 2013; Jain et al., 2011). same conditions until analyses. The informations about Morocco is one of the most date producing countries in samples are presented in Figure 1. the world (the 13th producer). the estimated production of dates in 2018 was 111.701 tones (FAOSTAT, 2018). There are 2.2. Physico-chemical analysis about 5.4 million palm trees in Morocco (Sedra 2015). Furthermore, the Mohammed VI Foundation for the 2.2.1. Soluble solids Protection of the Environment has planted 580.000 date palm (khalts and vitroplants) in the oasis of Marrakech The soluble solids (SS) were measured as °Brix in fruit which is known for its ornamental and unproductive juice with a hand refractometer (DR 6000, A. Kruss Optronic aspect (Meddich et al., 2015b). GmbH, Hamburg, Germany). 10 g of dates pulp were hydrated Previous studies analyzed the quality parameters in in 100 mL of distilled water and the juice was collected some Moroccan dates varieties (Hasnaoui et al., 2011; separately and centrifuged at 4000 rpm/ 15 min, and filtred Abba and Rochdi 2019). In this study, the quality properties through a Whatman No. 41 filter paper. The juice °Brix was and valuation of a none studied dates fruit clones from determined using refractometer (NF V 05-109,1970). southern Morocco (Zagora region) will be investigated. The aim of this study was to determine the compositional 2.2.2. Total titratable acidity and nutritional profile of the Moroccan date varieties and Total titratable acidity (TA) was measured in juice by clones in terms of the amounts of sugars, proteins, fats, titrating with 0.1N of sodium hydroxide in the presence of minerals and organic acids. phenolphthalein as indicator and the results were expressed as a percentage of citric acid. Titratable acidity was measured by mixing 25 g of fruit pulp with 50 mL of boiled distilled 2. Materials and Methods water in a blender and filtred, then, 25 mL of the filtrate (juice) was used for titration (NF V 05-101, 1974). 2.1. Plant materials and experimental procedure The present study was conducted using 4 Moroccan 2.2.3. Ash content date varieties and 13 clones as shown in Table 1, and The ash contents were obtained by incineration of 2 g were obtained at Tamar stage from different locations of date pulp in porcelain container at 600 °C in a muffle in Zagora region (Southern Morocco). The fruit samples furnace (Wise Therm, FHP-03, Korea) for 8h. Ash contents were collected and kept in a freezer at −20 °C in Zagora, were expressed as percent of dry matter. 2.2.4. Maturity index Table 1. Name and abbreviations of date varieties and clones. The ripening index (RI) is determined as the ratio of soluble Varieties and clones Abbreviations solids content and total titratable acidity (SS/TA). It is used as an indicator of taste quality. According to Melgarejo et al. Bourar BRR (2014), the ripening index can be a good indicator for good Black Bousthammi BST Variety Bouzegagh BZG Iklane IKL Bheir Ingli KBN Elahmer Chetoui ECT Elasfer Eljaid EED Elmensoum EMS Hak Feddan Laaneb HFL Khali Iaissi IAS Clone Khalt Abdelghani IAH Khalt Iaach KHL Khalt Khel KKL Khalt Lohmadi LHD Khalt Zoubair Ibn Laouam ZIE Mentouj Lhaj Lehbib MEL Figure 1. Map of Zagora of the date palm in Morocco as seen from Mentouj Tissgharine MTN space (Source: Google earth). 2/12 Brazilian Journal of Biology, 2022, vol. 82, e236471 Quality criteria of seventeen Moroccan dates fruit taste and can be a descriptive character in selecting 2.3.4. Determination of energy value cultivars for specific uses of fruit species. The energy value estimation of the date fruit varieties and clones was calculated by summing the multiplied 2.2.5. Determination of mineral contents values for crude protein, fat and carbohydrate by their The determination of the mineral contents was carried factors using formula described by Crisan and Sands out on ICP emission spectroscopy (inductively coupled (1978) as follows: plasma). Each sample was digested in 3 mL concentrated = × + × +× nitric acid (HNO3) and 3 mL concentrated hydrochloric Energy value (Kcal / 100 g) (2.62 % protein) (8.37 % fat) (4.2 % carbohydrate) acid (HCl) on a digestion block for 95 oC for 2h; then made Energy value (Kcal / 100 g) = (2.62 × % protein) + (8.37 × % fat) +× (4.2 % carbohydrate) up to a final volume 40 mL with ultrapure water. Each digest was then analyzed in triplicate. High purity single element standards were used for quantitation. All results 2.4. Statistical analysis were expressed as mg/100 g DW (dry weight). The results were statistically evaluated by the analysis of variance (ANOVA) using “XLSTAT Addinsoft TM” 2.2.6. Organic acids content software (XLSTAT 2014). Differences between the average Samples were accurately measured, and 1 g of the pulp data were compared using least significant difference date fruit was homogenized in 5 mL of deionized water (LSD) and statistical differences with P-values under and centrifuged at 10,000 × g for 15min. Supernatant was 0.05 were considered significant. A principal component then passed through a 0.45 µm filter before measurement.