Table 2.

Chemical analyses of the organic and inorganic constituents of coconut sap, sugar, and syrup.

	Studies
	Samples			Methodology	Analytical Details	Principal Outcomes	Ref.
	No.	Kind	Origin
Inorganic constituents	9 *	Coconut sugar	Ivory Coast	Spectrometry	Sample preparation: Coconut sugar was incinerated until ash was obtained. Sample processing: The coconut sugar ash analysis was performed by (SEM).	The mineral levels in coconut sugar samples fell within the ranges of 101.77–128.95 a (K), 85.32–94.66 a (Cl), 7.96–16.28 a (Mg), 12.68–15.87 a (Si), 8.33–14.57 a (P), 5.58–13.17 a (S), 8.05–11.65 a (Na), 1.23–2.19 a (Cu), and 1.73–2.09 a (Fe). Traces—1.04 a (Br) and 0.17 a (Zn). a—Values expressed as mg/100 g.	[35]
	1 *	Coconut sap	Malaysia (Jelai)	FAAS (flame atomic absorption spectrophotometry)	Sample preparation: Coconut sap was first diluted (10×), then filtered and further analyzed.	The predominant minerals were K (960.87 a), Na (183.21 a) and Mg (22.91 a). The levels of Fe (1.36 a), Ca (0.42 a), Zn (0.338 a), Mn (0.105 a) and Cu (0.065 a) were also determined. a—Values expressed as mg/L.	[36]
	6 *	Coconut sugar and coconut syrup	Philippines (Makati)	Atomic absorption spectrophotometry (AAS)	NR **	The mineral composition of both coconut sugar and coconut syrup was evaluated for 6 months. For coconut sugar, the K, Na, and Fe ranges were 954–1075 a, 99–112 a, and 0.5–0.6 a, respectively. The Ca and Zn levels remained constant over time and were 8 and 0.1 a, respectively. For coconut syrup, the levels of K varied between 609–632 a, Na between 110–126 a, Ca between 1–2 a, and Zn between 0.1–0.2 a. The Fe levels were 0.4 a at the three different measurement times. a—Values expressed as mg/100 g.	[31]
Organic constituents
Non volatiles
Amino acids	3 *	Coconut sap (collected by two different methods) and coconut sugar	India (Kasaragod)	Ninhydrin method (for free amino acids quantification) UHPLC-TQD-MS/MS (ultrahigh performance liquid chromatography coupled to tandem quadrupole mass spectrometry) for the amino acids profile analysis	Amino acids profile: Sample preparation: Samples were hydrolyzed in a vacuum using hydrochloric acid, 6 M. Then, hydrolysates were dried (also in a vacuum) after neutralization. They were dissolved in a known volume of the mobile phase, filtered (0.2 µm), and finally injected into the analytical system. Column: Waters UPLC BEH-C18 column (2.1 × 50 mm; 1.7 μm), protected by a Waters Vanguard BEH C-18 guard column (1.7 μm). Mobile phase: 0.1% formic acid in water-methanol: water (1:1) with 0.1% formic acid.	The total free amino acids content of the sap attained conventionally, the sap obtained from a “new coconut-sap chiller method”, and the sugar produced from the latter was, respectively 0.413 a, 1.03 a, and 3.05 b. The following amino acids were quantified in the coconut sap obtained by the traditional method: (i) glutamic acid (359 c); (ii) aspartic acid (83.7 c); (iii) serine (60.5 c); (iv) alanine (16.2 c); (v) threonine (13.7 c); (vi) proline (13.1 c); (vii) arginine (11.9 c); (viii) lysine (7.81 c); (ix) valine (6.48 c); (x) citrulline (6.38 c); (xi) methionine (5.90 c); (xii) phenylalanine (2.14 c); (xiii) asparagine (0.86 c); (xiv) leucine (0.64 c); (xv) histidine (0.42 c); (xvi) tyrosine (0.29 c); (xvii) tryptophan (0.01 c). For the sap acquired by the novel method, amino acids and respective levels were as follows: (i) glutamic acid (626 c); (ii) aspartic acid (118 c); (iii) serine (58.1 c); (iv) arginine (17.3 c); (v) alanine (15.1 c); (vi) proline (14.6 c); (vii) threonine (12.2 c); (viii) methionine (6.28 c); (ix) valine (6.10 c); (x) citrulline (6.07 c); (xi) lysine (5.93 c); (xii) phenylalanine (2.56 c); (xiii) asparagine (2.41 c); (xiv) histidine (0.65 c); (xv) leucine (0.56 c); (xvi) tyrosine (0.16 c); (xvii) tryptophan (0.01 c). In turn, sugar contained (i) glutamic acid (394 d); (ii) aspartic acid (131 d); (iii) proline (112 d); (iv) alanine (84.5 d); (v) serine (78.0 d); (vi) lysine (64.5 d); (vii) threonine (59.1 d); (viii) arginine (53.7 d); (ix) valine (50.9 d); (x) phenylalanine (50.7 d); (xi) tyrosine (26.0 d); (xii) leucine (21.8 d); xiii) methionine (19.6 d); (xiv) histidine (5.83 d); (xv) citrulline (5.79 d); (xvi) asparagine (4.25 d); (xvii) 3,4-dihydroxy-phenylalanine (0.76 d); (xviii) tryptophan (0.18 d). a—Values appear as g/100 mL; b—Values appear as g/100 g; c—Values appear as mg/100 mL. d—Values appear as mg/100 g	[21]
Carbohydrates	3 *	Coconut syrup (produced by three different methods)	Malaysia (Jelai)	HPLC-RID (high-performance liquid chromatography coupled with refractive index detection)	Sample preparation: Coconut syrup samples were diluted (10×), filtered (0.45 µm), and further analyzed. Column: Merck LiChroCART® Single bond NH2 column (250 × 4.6 mm; 5 µm). Mobile phase: Acetonitrile-water (80:20, v/v).	The authors investigated the processing of coconut sap in syrup by alternative process techniques compared to the conventional open heat evaporation technique. The fructose, glucose. and sucrose levels respectively ranged between 18.27–35.07 a, 21.38–23.71 a, and 7.35–25.67 a. The coconut syrup obtained by the rotary evaporation technique displayed larger quantities of glucose and fructose, but a smaller quantity of sucrose, than that produced by the other techniques. The total sugar content for all the analyzed samples was between 64.89–65.66 a. a—Values expressed as %.	[22]
	1 *	Coconut sap	Malaysia (Jelai)	HPLC-RID (high-performance liquid chromatography coupled with refractive index detection)	Sample preparation: Coconut sap was diluted, (10×), filtered (0.45 µm), and further analyzed. Column: Merck LiChroCART® Single bond NH2 column (250 × 4.6 mm; 5 µm). Mobile phase: Acetonitrile-water (80:20, v/v).	Three sugars (sucrose, fructose, glucose) were detected in coconut sap. Their respective values were 6.91 a, 3.48 a, and 2.53 a. a—Values expressed as %.	[36]
	3 *	Coconut sap (collected by two different methods) and coconut sugar	India (Kasaragod)	Phenol–sulphuric acid method (for total sugars content determination) Nelson-Somogyi’s method (for reducing sugars content quantification)	NR **	The total sugars content of the sap acquired traditionally, the sap obtained following a new “coconut-sap chiller method”, and the sugar produced from the latter was 9.20 a, 16.2 a, and 91.8 b, respectively. For the reducing sugars content, the reported values were 1.24 a for the sap obtained conventionally, 0.68 a for the sap collected by the novel approach, and 4.69 b for sugar. a—Values shown as g/100 mL; b—Values shown as g/100 g.	[37]
	6 *	Coconut sugar and coconut syrup	Philippines (Makati)	GC–MS (gas chromatography-mass spectrometry)	NR **	The sugar composition of both coconut sugar and coconut syrup was evaluated for 6 months. For coconut sugar, the sucrose, glucose, fructose, and mannose levels ranged between 83.18–90.50 a, 9.40–11.45 a, 2.89–3.69 a, and 0.51–3.90 a, respectively. For coconut syrup, they varied between 35.85–38.96 a, 10.74–14.03 a, 15.39–15.57 a, and 3.91–5.35 a, respectively. a—Values expressed in mg/100 g.	[38]
	4 *	Coconut sap (with and without preservative, i.e., limestone solution) and coconut sugar (with and without preservative)	Kemloko (Indonesia)	HPLC-RID (high-performance liquid chromatography coupled with refractive index detection)	Sample preparation: For each sample, 1 g was weighed, and then dissolved in 100 mL of distilled water. The mixture was filtered, and the solution was injected into the HPLC. system. Column: Aminex HPX-87C. Mobile phase: Water.	For the fresh sap to which no preservative was added, lower sucrose content (1.76 a) and higher fructose (5.76 a) and glucose (4.46 a) contents were found compared to the sap with the preservative whose sucrose, fructose and glucose levels were 5.76 a, 3.23 a, and 2.25 a, respectively. For coconut sugar, the sucrose content of that prepared with fresh coconut sap, but without adding a preservative, was lower (49.41 a) than that of coconut sugar produced with the fresh coconut sap to which a preservative was added (49.41 vs. 57.05 a). Their glucose (15.90 a) and fructose (14.15 a) levels were higher than those of the coconut sugar prepared from the fresh coconut sap to which a preservative was added; that is, glucose 6.97 a and fructose 5.45 a. a—Values expressed in %.	[32]
Phenolics	3 *	Coconut sap (collected by two different methods) and coconut sugar	India (Kasaragod)	Folin’s Ciocalteu method (for total phenolic content determination purposes) Ultrahigh performance liquid chromatography coupled with UHPLC-TQD-MS/MS (tandem quadrupole mass spectrometry) for the phenolic profile analysis	Phenolic profile: Sample preparation: The extraction of the individual phenolics was performed with 80% aqueous methanol (v/v). Thereafter, filtering the extracted sample was performed (0.2 μm). This sample was injected into the analytical system. Column: Waters UPLC BEH-C18 column (2.1 × 50 mm; 1.7 μm) protected by a Waters Vanguard BEH C-18 guard column (1.7 μm). Mobile phase: 0.1% formic acid in water 0.2% formic acid in methanol	The total phenolics content of the sap acquired traditionally, the sap obtained by a novel “coconut-sap chiller method”, and the sugar produced from the latter was 14.8 a, 21.7 a, and 47.2 b, respectively. The following phenolic compounds were quantified in the coconut sap obtained by the traditional method: (i) vanillic acid (2.92 c); (ii) syringic acid (1.80 c); (iii) trans-cinnamic acid (0.636 c); (iv) p-hydroxy benzoic acid (0.308 c); (v) ferulic acid (0.302 c); (vi) protocatechuic acid (0.182 c); (vii) 2,4-dihydroxy benzoic acid (0.126 c); (viii) gentisic acid (0.104 c); (ix) gallic acid (0.073 c); (x) o-coumaric acid (0.064 c); (xi) rutin (0.043 c); (xii) caffeic acid (0.042 c); (xiii) salicylic acid (0.040 c); (xiv) umbelliferone (0.030 c); (xv) p-coumaric acid (0.008 c). Regarding the sap collected by the new method, the identified phenolics were as follows: (i) vanillic acid (3.54 c); (ii) trans-cinnamic acid (2.40 c); (iii) p-hydroxy benzoic acid (0.963 c); (iv) syringic acid (0.707 c); (v) salicylic acid (0.477 c); (vi) ferulic acid (0.246 c); (vii) catechin (0.157 c); (viii) quercetin (0.156 c); (ix) hesperetin (0.116 c); (x) myricetin (0.105 c); (xi) caffeic acid (0.103 c); (xii) rutin (0.078 c); (xiii) protocatechuic acid (0.065 c); (xiv) o-coumaric acid (0.062 c); (xv) umbelliferone (0.056 c); (xvi) gallic acid (0.044 c); (xvii) p-coumaric acid (0.030 c); (xviii) gentisic acid (0.026 c); (xix) 2,4-dihydroxy benzoic acid (0.015 c). In sugar: (i) vanillic acid (12.8 d); (ii) benzoic acid (9.41 d); (iii) trans-cinnamic acid (4.25 d); (iv) catechin (2.37 d); (v) p-hydroxy syringic acid (1.96 d); (vi) p-coumaric acid (1.27 d); (vii) ferulic acid (0.908 d); (viii) o-coumaric acid (0.706 d); (ix) salicylic acid (0.653 d); (x) myricetin (0.390 d); (xi) hesperetin (0.327 d); (xii) quercetin (0.313 d); (xiii) apigenin (0.230 d); (xiv) protocatechuic acid (0.224 d); (xv) gallic acid (0.203 d); (xvi) rutin (0.192 d); (xvii) gentisic acid (0.111 d); (xviii) caffeic acid (0.109 d); (xix) umbelliferone (0.078 d); (xx) 2,4-dihydroxy benzoic acid (0.037 d). a—Values are mg of gallic acid equivalents (GAE)/100 mL; b—Values are mg of GAE/100 g; c—Values are mg/100 mL; d—Values are mg/100 g.	[21]
Vitamins	1 *	Coconut sap	Malaysia (Jelai)	HPLC/UV-Vis (high-performance liquid chromatography coupled with ultraviolet-visible detection)	Sample preparation: Coconut sap was diluted (10x), filtered, and further analyzed. Column: Agilent Poroshell 120 EC column (100 × 4.6 mm; 4 μm). Mobile phase: Potassium dihydrogen phosphate buffer (pH 3.4, 50 mM).	Vitamins C, B1, B2, B3, B4, and B10 were all detected in coconut sap. Their levels were 116.19 a, 4.33 a, 0.084 a, 1.88 a, 0.53 a, and 0.33 a, respectively. a—Values expressed as µg/mL.	[36]
	3 *	Coconut sap (collected by two different methods) and coconut sugar	India (Kasaragod)	6-Dichlorophenol-indophenol (DCPIP) method for vitamin C level measurements (ultrahigh performance liquid chromatography coupled to tandem quadrupole mass spectrometry) for the quantification of other vitamins	Sample preparation: Water-soluble vitamins: Samples were extracted with 10 mM ammonium acetate:methanol 50:50 (v/v) that contained 0.1% butylhydroxytoluene and centrifuged. Next, the supernatant was (0.2 μm) filtered and injected into the analytical system. Fat-soluble vitamins: The residue from the previously described extraction (please refer to “water-soluble vitamins”) was re-extracted with ethyl acetate that contained 0.1% butylhydroxytoluene, centrifuged and filtered (0.2 μm) before being injected into the analytical system. Column: Waters UPLC BEH-C18 column (2.1 × 50 mm; 1.7 μm) protected by a Waters Vanguard BEH C-18 guard column (1.7 μm). Mobile phase: Water-soluble vitamins: 0.1% formic acid in water- acetonitrile. Fat-soluble vitamins: Acetonitrile—0.2% formic acid in methanol.	The following vitamins were detected and quantified in the coconut sap obtained by the traditional method: (i) vitamin C—16.3 a; (ii) B1—0.021 c; (iii) B3—11.4 c; (iv) B5—1.64 c; (v) B6—1.32 c; (vi) B7—0.095 c; (vii) B9—0.031 c; (viii) D2—0.028 c; (ix) D3—0.062 c; (x) E—2.94 c; (xi) K1—0.601 c; (xii) K2—0.428 c. For the sap collected by a new “coconut-sap chiller method”, the vitamins and their respective levels were as follows: (i) vitamin C—19.6 a; (ii) B1—0.068 c; (iii) B3—14.9 c; (iv) B5—3.99 c; (v) B6—2.35 c; (vi) B7—0.073 c; (vii) B9—0.036 c; (viii) D2—0.074 c; (ix) D3—0.056 c; (x) E—7.20 c; (xi) K1—1.73 c; (xii) K2—0.771 c. Sugar contained (i) vitamin C—3.98 b; (ii) B1—14.3 d; (iii) B2—0.248 d; (iv) B3—34.7 d; (v) B5—2.53 d; (vi) B6—101 d; (vii) B7—2.51 d; (viii) B9—0.260 d; (ix) D2—0.171 d; (x) D3—0.256 d; (xi) E—19.6 d; (xii) K1—7.35 d; (xiii) K2—5.57 d. a—Values are given as mg/100 mL; b—Values are given as mg/100 g; c—Values are given as µg/100 mL; d—Values are given as µg/100 g.	[21]
	6 *	Coconut sugar and coconut syrup	Philippines (Makati)	2,6-Dichloroindophenol titrimetric method	NR **	Vitamin C levels in both coconut sugar and coconut syrup were evaluated over 6 months and ranged from 16 to 44 a for the former, and from 19 to 30 a for the latter. a—Values expressed as mg/100 g.	[31]
Volatiles
Aliphatic/aromatic hydrocarbons, ketones, aldehydes, alcohols, esters, fatty acids, furans, pyrazines, pyrans and sulfur-containing compounds.	3 *	Coconut sap (fresh, clarified, and fermented)	India (Mandakalli)	GC–MS (gas chromatography-mass spectrometry)	Isolated volatiles: Volatile compounds were isolated by the SDE (simultaneous distillation-extraction) method with a Likens-Nikerson apparatus. The extractive solvent was dichloromethane. GC–MS: Column: Supelco-fused silica column SPB-1 (30 m × 0.32 mm; 0.25 µm) coated with polydimethyl siloxane. Gas carrier: Helium.	The following 21 compounds were identified in the fresh coconut sap: (i) palmitic acid (2024 a); (ii) palmitoleic acid (1042 a); (iii) ethyl lactate (560 a); (iv) phenyl ethyl alcohol (357 a); (v) 3-hydroxy-2-pentanone (236 a); (vi) tetradecane (167 a); (vii) farnesol (125.5 a); (viii) 2-methyl tetrahydrofuran (105 a); (ix) tetradecanone (104.5 a); (x) tetradecanoic acid (94.0 a); (xi) nonanoic acid (84.8 a); (xii) dodecane (74.3 a); (xiii) dodecanoic acid (52.6 a); (xiv) hexanoic acid (49.8 a); (xv) pentadecane (48.4 a); (xvi) 2-hydroxy-3-pentanone (45.6 a); xvii) nerolidol (44.9 a); (xviii) hexadecane (37.2 a); (xix) 1-hexanol (27.3 a); (xx) hexadecanone (25.9 a); (xxi) tridecanone (24.5 a). For the clarified coconut sap, 13 compounds were identified, which were as follows: (i) palmitic acid (342 a); (ii) ethyl lactate (300 a); (iii) phenyl ethyl alcohol (195 a); (iv) palmitoleic acid (141 a); (v) 3-hydroxy-2-pentanone (75.9 a); (vi) hexanoic acid (54.7 a); (vii) tetradecane (46.9 a); (viii) 2-methyl tetrahydrofuran (45.4 a); (ix) dodecane (30.5 a); (x) 1-hexanol (24.8 a); (xi) pentadecane (21.8 a); (xii) hexadecane (16.4 a); (xiii) 2-hydroxy-3-pentanone (14.0 a). In the fermented coconut sap, 11 compounds were identified, namely as follows: (i) palmitoleic acid (14,603 a); (ii) isoamylalcohol (7467 a); (iii) ethyl lactate (4636 a); (iv) phenyl ethyl alcohol (4189 a); (v) palmitic acid (2421 a); (vi) dodecanoic acid (1084 a); (vii) ethyl caprate (797 a); (viii) ethyldodecanoate (709 a); (ix) tetradecanoic acid (597 a); (x) ethyl caprylate (503 a); (xi) farnesol (224 a). a—Values expressed as µg/L.	[12]
	6 *	Coconut sap, coconut syrup and coconut sugar	Indonesia (Blitar)	Gas chromatography—mass spectrometry (GC–MS)	Isolated volatiles: Volatile compounds were isolated by a simultaneous distillation–extraction (SDE) method using a Likens–Nikerson apparatus. The extractive solvent was diethylether. GC–MS: Column: CBP-5 column (50 m). Gas carrier: Helium.	Five volatiles were isolated in the fresh coconut sap: (i) 2-butanol (60.26–68.37 a); (ii) acetic acid (25.83–30.43 a); (iii) 2-methylcyclohexane (0.66–6.39 a); (iv) cyclohexyloctane (1.81–4.23 a); (v) 1,4 dimethyl-6,1-butyl acetate (0.91–1.11 a). For coconut syrup, the following occurred: (i) 2-butanol (45.35–51.02 a); (ii) acetic acid (24.56–6.47 a); (iii) dodecanoic acid (0.34–21.59 a); (iv) 2-furan (1.97–6.73 a); (v) cyclohexane (3.56–4.41 a); (vi) 1,4 dimethyl-6,1-butyl acetate (0.40–10.26 a); (vii) 4,6 dimethyl-5-cyclo-hexo pyrimidine (0–2.25 a); (viii) 2,3 dimethylpirazine (0–0.77 a). Finally for coconut sugar, the following compounds were identified: (i) acetic acid (21.54–35.05 a); (ii) 2-butanol (29.98–31.23 a); (iii) 1,4 dimethyl-6,1-butyl acetate (1.7–15.50 a); (iv) N,N dimethyl 2-(diphenylmetoxi)-ethylamine (9.31–13.26 a); (v) cyclohexyloctane (0.0–17.01 a); (vi) dodecanoic acid (0.0–12.41 a); (vii) methylpyrazine (1.46–1.81 a). a—Values expressed as %.	[37]
	1 *	Coconut sugar	Thailand (Samutsongkhram)	GC–MS (gas chromatography-mass spectrometry) GGO (gas chromatography-olfactometry)	Isolated volatiles: Volatile compounds were extracted three times with diethyl ether. The combined extract was left to concentrate in a Vigreux column. Then, the concentrated extract was subjected to high vacuum distillation and then concentrated, first in a Vigreux column and finally in a nitrogen flow. GC–MS: Column: Restek Stabilwax column (30 m × 0.25 mm; 0.25 µm) and an Agilent DB-5MS column (30 m × 0.25 mm; 0.25 µm). Gas carrier: Helium. Descriptive sensory analysis: The sensory evaluation panel included nine properly trained evaluators.	The following volatile compounds were identified in coconut sugar: (i) acetic acid a; (ii) 2,3-pentanedione; (iii) acetoin; (iv) 2,5-dimethyl pyrazine; (v) 2,3-butanedione; (vi) methional; (vii) furfural; (viii) 5-methyl furfural; (ix) 2-furanmethanol; (x) 4-methyl-5H-furan-2-one; (xi) 5-methyl-2-furan methanol; (xii) benzylalcohol; (xiii) maltol [3-Hydroxy-2-methyl- 4H-pyran-4-one]; (xiv) Furaneol® [2,5-dimethyl-4- hydroxy-3(2H)-furanone]; (xv) vanillin [4-Hydroxy-3- methoxybenzaldehyde]. The sweet, roasted, burnt, nutty, smoky, and caramel notes of coconut sugar were attributed mostly to pyrazine, furan, and pyran derivatives being present. Benzyl alcohol and vanillin also introduce sweet notes. In addition, acetoin, 2,3-pentanedione and 2,3-butanedione were found to be responsible for the buttery, cheesy, and creamy aromas. a—Major component identified; values not reported.	[38]
	2 *	Coconut sugar	Thailand (Ampawa)	GC–MS (gas chromatography–mass spectrometry)	Isolated volatiles: Volatile compounds were extracted by SPME (solid-phase microextraction). GC–MS: Column: An Agilent DB-625 capillary column (30 m × 0.25 mm). Gas carrier: Helium.	The identified volatile compounds were as follows: (i) 2,3-diethyl-5-methyl pyrazine; (ii) 2,3-dimethyl pyrazine; (iii) 2,5- dimethyl pyrazine; (iv) 2-ethyl-3,5-dimethyl pyrazine; (v) 2-methyl pyrazine; (vi) ethyl pyrazine; (vii) 5-methyl furfural; (viii) furfural.	[12]
	2 *	Coconut sugar	Thailand (Samut Songkhram and Phetchaburi)	GC–MS (gas chromatography–mass spectrometry)	Isolated volatiles: Volatile compounds were isolated by means of headspace gas chromatography. GC–MS: Column: An Agilent DB wax-fused silica capillary column (60 m × 0.25 mm; 0.25 µm). Gas carrier: Helium.	The detected volatile components comprised the following: (i) ethanol (9.48–52.21 a); (ii) 4-methanol (19.58–27.85 a); (iii) acetaldehyde (<0.01–16.33 a); (iv) 2-furanmethanol (<0.01–13.54 a); (v) acetic acid (<0.01–11.98 a); (vi) 1-hydroxy-2-propanone (<0.01–10.24 a); (vii) acetone (2.63–9.98 a); (viii) 2-ethyl-3,6-dimethyl pyrazine (<0.01–6.46 a); (ix) 2-propanol (2.29–4.37 a); (x) hexanoic acid (<0.01–2.93 a); (xi) 3-methyl hexanal (<0.01–2.35 a); (xii) 2-furaldehyde (<0.01–1.48 a); (xiii) hydroxy-2-butanone (0.0–1.10 a); (xiv) butanoic acid (<0.01–1.01 a); (xv) 2-methyl propanal (0–0.91 a); (xvi) 3-(methylthio)-propanal (<0.01 a); (xvii) 2,3-butanedione (<0.01 a); (xviii) 2-methyl-3-buten-2-ol (<0.01 a); (xix) 2-methyl-1-propanol (<0.01 a); (xx) 2-ethyl-5-methyl pyrazine (<0.01 a); (xxi) 3-methyl-butanol (<0.01 a); (xxii) 2-acetylfuran (<0.01 a). a—Values expressed as %.	[34]

* Total number of samples analyzed in the study; ** NR—Not reported.