Vitamin B complex, amino acid profile and bioactive properties of newly developed rye variants

ABSTRACT

This study was designed to investigate the amino acid profile, vitamin B complex, and bioactive properties present in recently cultivated rye variants in Pakistan. The four rye variants, named as Gp 1, Gp-2, Gp-3, and Gp-4, were procured from the Forage and Pulses section of AARI Faisalabad. The rye samples were ground into flour using a hammer-type 120-ton laboratory mill. For the analysis of amino acids, vitamin B complex, phenolic constituents, alkylresorcinols, and lignin, standard HPLC and GC-MS methods were employed following the extraction with appropriate reagents. The results revealed that among the rye variants, Gp-2 showed the highest content of vitamin B complex, with thiamin at 252.33 μg/100 g, niacin at 397 μg/100 g, and pyridoxine at 99 μg/100 g. Pantothenic acid (246.70 μg/100 g) and ascorbic acid (470 μg/100 g) were found in the highest concentrations in Gp-3. The riboflavin content of Gp-1 was 84.40 g/100 g, while the folate content of Gp-4 was 24.40 g/100 g. In terms of phenolic compounds, the range of chlorogenic acid content ranged from 86.70 to 92.43 mg/kg, p-coumaric acid from 2.70 to 5.40 mg/kg, gallic acid from 64.70 to 97.10 mg/kg, caffeic acid from 16.90 to 25.90 mg/kg, and coumaric acid from 218.10 to 228.40 mg/kg. In conclusion, Gp-2 observed as the most nutritionally rich and bioactive variant, distinguished by its high essential amino acids, vitamins, and other bioactive components.

KEYWORDS:

• Secale cereal L
• amino acid
• vitamin
• phenolic
• Lignan
• Alkylresorcinol

Introduction

Rye (Secale cereal L.) is a neglected crop in terms of overall production in the world. Rye contributes to approximately 0.70% of the entire cereal crops. The global data regarding rye production is expected to be about 14.80 million tons. Rye grains are unusually winter hardy and can thrive in sandy, allowing them to be grown in regions where other cereals cannot grow.^[1] It is believed to have originated from Asian wild rye types, particularly wheat flour, which spread like weeds^[2]

In cereals, rye contains higher total dietary fiber (24.47%) and various bioactive constituents.^[3] Many Nordic countries have a long-standing and rich history of including rye in their diets.All cereals, especially rye, should be baked with whole-grain flour since whole rye grains are rich in vitamins, fibers, minerals and other bioactive substances^[4]

Plant-derived phytochemicals are essential components used by plants for both defense systems and cell signaling processes.Aleurone cells, or the bran layer, are an essential source of various phytochemicals.^[5,6] Rye has been found to contain benzoxazinoids, phenolic acids, lignans and alkylresorcinols.^[7] However, rye comprises over 2000 chemicals as a result of the continuous increase in the number of phytochemicals that have been identified in the rye.^[8] Therefore, rye consumption on a daily basis has found to be significantly protective against a number of diseases in recent research.^[9] Rye grains contain minerals as well as carbohydrates, protein, fiber and amino acids, particularly lysine content. They also have vitamins E and B complex, which includes thiamine, folic acid, pantothenic acid and riboflavin. Rye contains less gluten than wheat on average.^[10]

Delcour & Hoseney^[11] found that the biochemical profile of rye is affected by variety, climate and farming circumstances, quality of land and other factors. Rye grain has a basic makeup that is comparable to that of other cereals.^[12] The major component of rye seed is starch. Rye starch gelatinization occurs at a lower temperature as compared to wheat starch. The size of starch fraction (A-type 20–35 μm), and (B-type 5–10 μm) and shape (spherical and lenticular) of rye starch contents are comparable to wheat starch.^[13] Compared to wheat starch, rye flour starch granules have more enzymatic and mechanical degradation. Rye flours have fewer proteins and starch than wheat, but more fiber.^[3] The aleurone layer of rye endosperm is high in bioactive components like phenolic compounds (phenolic acids and polyphenols), vitamins (B vitamins, particularly riboflavin, thiamine, niacin as well as vitamin E), minerals (potassium, iron, zinc, magnesium and phosphorus), lignans, sterols, alkylresorcinols as well as stanols.^[14] Secondary metabolites of cereal compounds that are bioactive compounds include phenolics, i.e. flavonoids, flavanones, and isoflavones.^[15] This project aims to investigate the amino acid profile, vitamin B complex composition, and presence of important bioactive chemicals in different wholegrain rye variants, with a focus on lignans, alkylresorcinols, and phenolics.

Materials and methods

Procurement of raw materials

Grains of rye were procured from Forage and pulses Section, Ayub Agricultural Research Institute AARI, Faisalabad. RJS-1001, RJS-1002, RJS-1003 and RJS-1004 were four variations that were GP-1, GP-2, GP-3 and GP-4, respectively. For the analysis, only chemicals of analytical grade were used. H₂SO₄ and methanol are obtained from Sigma-Aldrich Chemical Co. (St. Louis, MO, USA) whereas, n-hexane and petroleum ether were purchased from Merck (Darmstadt, Germany). Rye grains were ground at Ayub Agricultural Research Institute, Faisalabad using a hammer-type 120 perton laboratory mill. The ground flour was separated using sieves that varied in size from 0.5 to 2.0 mm. This paper is a fouth part of a PhD research project. The other parts of the projects are already published^[2,4,8]

Amino acid profile

Five-gram rye flour samples with 80% aqueous ethanol (10 mL) were put in a cylinder glass tube. At 110°C the glass tube containing the sample was hydrolyzed for 24 h. After adding 5 mL of distilled water to the samples, they were centrifuged for 10 min at 4000 rpm and 4°C. The supernatant was removed and filtered by a 0.45 µm syringe filter and put into a flask. Three percent of 1 mL sulfosalicylic acid (SSA) was added to the flask. The SSA samples were mixed under the vortex until homogenous and placed at 20°C. The solution was again centrifuged for 10 min at 4000 rpm and 4°C. The supernatants were withdrawn and dried at 45°C. To dissolve the solution, 1 mL of sodium acetate buffer was added. A 0.22 µm filter was used to filter the solution once more. About 300 µL of the filtrate was ready to be transferred to the Central Hi-Tech Lab, Government College University Faisalabad, Pakistan. The sample of 50 nmoL/mL was analyzed using a JEOL (JLC 500/V) automatic amino acid analyzer. The amino acids were measured in g/100 g of dry weight protein.

Vitamins B profile

Sample preparation

With slight modifications, the rye samples were treated as described in Aslam et al.^[16] to analyze B vitamins. Ten grams of homogenized rye flour were transferred into a conical flask. The extraction mixture was then added to the sample in a volume of 25 mL. For 40 min, samples and extraction solution were maintained at 70°C in the water bath. The samples were then cooled for 3–4 h before being filtered.

HPLC analysis

Using HPLC (Perkin Elmer series 200), the Shim-pack GIST-HP (Octadecylsilane (C18) column was used for quantification (4.6 × 250 mm 5 µm). Buffer: methanol (96:4; v/v) was used in a linear gradient at a constant flow rate of 1 mL/minThe samples were measured at the wavelengths 210 nm and 280 nm.

Phenolic compounds

According to the methods proposed by Irmak et al.,^[17] phenolic acids were calculated of rye flour. The primary phenolic acids were determined using HPLC (Perkin Elmer series 200) with a UV-visible detector. The Shim-pack GIST-HP (Octadecylsilane (C18) column was used.

Alkylresorcinols content

The procedure proposed by Mattila et al.^[18] was used to determine alkylresorcinols. The sample (1.25 g) was steeped at ambient temperature in a Pyrex screw-cap tube with an equivalent weight of acetone. The extract was saved after being filtered using Whatman No. 1 paper for 24 hours. After 24 hours, the sample was again submerged in the same volume of acetone and filtered. Previous extracts were mixed with filters. Sample was dried and powdered before being re-soaked in acetone in a 1:5 ratio, filtered, and then added to the earlier extract. With the help of acetone, the volume of collected extracts was increased to 25 ml. A water bath at 850°C was used to extract the acetone from two aliquots of 2.0 ml each that had been transferred to Pyrex screw-cap tubes lined with Teflon. After being brought to room temperature, the leftover was dissolved in 0.4 cc of chloroform. The tube was sealed tightly after being filled with 0.1 ml of 75% ethanol and 0.1 ml of 75% KOH. It was then put in a shaker bath at 450 C and stirred every 2–3 minutes.

After 20 minutes, 8.4 ml of 95% ethanol and 1.0 ml of distilled water were added. 10 ml in total were shaken, and they were let to stand for 30 minutes. The tube was shaken once more before to detecting the fluorescence on a Hitachi Perkin-Elmer MPF-2A spectrofluorometer (Perkin-Elmer, Norwalk, CT). The wavelengths used for excitation and emission were 420 and 520 nm, respectively. With each set of samples, a standard curve was created using 5-pentadecylresorcinol. To confirm the precision of the response factors calculated from olivetol, the standards C17:0, C19:0 and C21:0 (ReseaChem GmbH, Burgdorf, Switzerland) were used. The results are given in mg/100 g of dry weight.

Lignin contents

GC-MS (Agilent 7000E triple quadrupole GC/MS) was used to identify lignans including pinoresinol, matairesinol, isolariciresinol, secoisolariciresinol, lariciresinol and syringaresinol, with minor changes in the procedure suggested by Mazur et al.^[19] The standards (50 mg) and distilled water were added to the weighed quantity of the sample. Enzymatic hydrolysis was used to prepare the samples before extraction with diethyl ether. Hydrochloric acid was used to hydrolyze in the water phase, which was then extracted using a combination of diethyl ether and ethyl acetate. Ion exchange chromatography was used to mix and purify the organic phases, as reported by Mazur et al.^[19] The treated samples were analyzed by GC – MS after silylation.

Results and discussion

Essential amino acid profile

The mean value of the isoleucine content of whole rye flour is presented in Figure 1. The present study’s findings indicated that the isoleucine lysine, phenylalanine, threonine, tryptophan, valine, histidine, leucine and methionine content in the rye flour varied from 225 to 254.67, 195 to 256, 192 to 226, 178 to 201.3, 46 to 68, 265.3 to 325, 135.67 to 157, 356.33 to 395, and 43.1 to 49 g/kg N⁻¹ respectively. The maximum isoleucine, content (254.67 g/kg N⁻¹) was detected in Gp-4 while, the minimum isoleucine content was detected in Gp-3 (225 g/kg N⁻¹). The highest lysine content (256 g/kg N⁻¹) was detected in Gp-3 while, the lowest lysine content was detected in Gp-1 (195 g/kg N⁻¹). On the other hand, the grain protein of rye has a greater lysine concentration (15.1–28.1) than wheat (13.1–24.9).^[13] Meanwhile, The maximum phenylalanine content (226 g/kg N⁻¹) was detected in Gp-1 although, the minimum phenylalanine content was detected in Gp-4 (192 g/kg N⁻¹). The highest threonine content (201.3 g/kg N⁻¹) was detected in Gp-4 whilst, the lowest threonine content was detected in Gp-1 (178 g/kg N⁻¹). In comparison, The maximum tryptophan content (68 g/kg N⁻¹) was detected in Gp-1 while, the minimum tryptophan content was detected in Gp-3 (46 g/kg N⁻¹). The highest valine content (325 g/kg N⁻¹) was detected in Gp-1 whilst, the lowest valine content was detected in Gp-3 (265.3 g/kg N⁻¹).

Figure 1. Mean values for the essential amino acid contents of four different rye flours (g/kg N⁻¹).

The maximum histidine content (157 g/kg N⁻¹) was detected in Gp-3 whilst, the minimum histidine content was detected in Gp-1 (135.67 g/kg N⁻¹). The highest leucine content (395 g/kg N⁻¹) was detected in Gp-4 whilst, the lowest leucine content was detected in Gp-1 (356.3 g/kg N⁻¹). The maximum methionine content (49 g/kg N⁻¹) was detected in Gp-1 whilst, the minimum methionine content was detected in Gp-4 (43.1 g/kg N⁻¹).

Similar findings regarding the amino acid content were noticed by McKevith^[14] who detected that the isoleucine, lysine, phenylalanine, threonine, tryptophan, valine, histidine, leucine and methionine content in the rye flour were 3.7 to 4.9, 3.5, 5, 3.1, 0.8, 4.9, 2.4, 6.4 and 1.6 g/100 g, respectively. Furthermore, another study conducted by Kowieska et al.^[20] presented that the average isoleucine, lysine, phenylalanine, threonine, tryptophan, valine, histidine, leucine and methionine content in the rye flour varied from 3.5 to 5.2, 3.4 to 4.7, 4.5 to 5.6, 3.4 to 5.4, 0.9 to 1.8, 4.64 to 5, 2.05 to 2.19, 5.77 to 6.38 and 0.94 to 0.99 g/100 g, respectively. Aho and Koivistoinen^[21] also depicted that the average isoleucine, lysine, phenylalanine, threonine, tryptophan, valine, histidine, leucine and methionine content in rye flour is 3.01, 3.05, 4.14, 2.86, 0.61, 4.8, 2.83, 6.71 and 0.96 g/16 g N⁻¹, respectively. The results are also in harmony with the outcomes of Kihlberg and Ericson^[22] who reported that the isoleucine, lysine, phenylalanine, threonine, tryptophan, valine, histidine, leucine and methionine contents in rye flour are 3.76, 3.84, 5.6, 3.87, 1.1, 5.03, 2.2, 5.24 and 1.32%, respectively. Similar outcomes are also depicted by Rodehutscord et al.^[23] who mentioned that the average isoleucine, lysine, phenylalanine, threonine, tryptophan, valine, histidine, leucine and methionine contents in the rye flour were between 2.51 to 3.1, 3.29 to 3.75, 4.57 to 4.84, 3.13 to 3.34, 0.96 to 1.08, 3.62 to 4.29, 2.38 to 3.91, 5.86 to 6.32 and 1.43 to 1.62 g/16 g N⁻¹.

Non-essential amino acid

The mean value of the non-essential amino acid content of whole rye flour is presented in Figure 2. The present study’s findings indicated that the arginine content in the rye flour varied from 258.6 to 280 g/kg N⁻¹. The highest arginine content (280 g/kg N⁻¹) was detected in Gp-2 then Gp-1 (274 g/kg N⁻¹) and Gp-3 (271 g/kg N⁻¹) whilst the lowest arginine content was detected in Gp-4 (258.6 g/kg N⁻¹). However, the aspartic acid in the rye flour varied from 308 to 326.6 g/kg N⁻¹. The maximum aspartic acid (326.6 g/kg N⁻¹) was detected in Gp-3 then Gp-4 (319 g/kg N⁻¹) and Gp-2 (314.3 g/kg N⁻¹) whilst minimum aspartic acid was noticed in Gp-1 (308 g/kg N⁻¹). Moreover, the glycine in the rye flour varied from 245.4 to 265.6 g/kg N⁻¹. The highest glycine (265.6 g/kg N⁻¹) was detected in Gp-4 then Gp-2 (255.3 g/kg N⁻¹) and Gp-1 (255 g/kg N⁻¹) whilst the lowest glycine was detected in Gp-3 (245.4 g/kg N⁻¹). The tyrosine in the rye flour varied from 56 to 78.6 g/kg N⁻¹. The highest tyrosine (78.6 g/kg N⁻¹) was determined in Gp-3 then Gp-4 (69.6 g/kg N⁻¹) and Gp-1 (64.16 g/kg N⁻¹) whilst minimum tyrosine was detected in Gp-2 (56 g/kg N⁻¹). While, the alanine in the rye flour varied from 236 to 255 g/kg N⁻¹. The highest alanine (255 g/kg N⁻¹) was detected in Gp-4 then Gp-3 (252 g/kg N⁻¹) and Gp-1 (247.6 g/kg N⁻¹) whilst the lowest alanine was detected in Gp-2 (236 g/kg N⁻¹). Although, the cysteine in the rye flour varied from 62.9 to 74.6 g/kg N⁻¹. The highest cysteine (74.6 g/kg N⁻¹) was detected in Gp-2 then Gp-1 (73.8 g/kg N⁻¹) and Gp-3 (63.9 g/kg N⁻¹) whilst minimum cysteine was detected in Gp-4 (62.9 g/kg N⁻¹). The glutamic acid in the rye flour varies from 1429 to 1494 g/kg N⁻¹. The maximum glutamic acid (1494 g/kg N⁻¹) was examined in Gp-2 then Gp-3 (1466.3 g/kg N⁻¹) and Gp-1 (1459 g/kg N⁻¹) whilst minimum glutamic acid was detected in Gp-4 (1429 g/kg N⁻¹). Whereas, the proline in the rye flour varied from 484.3 to 512.3 g/kg N⁻¹. The highest proline (512.3 g/kg N⁻¹) was detected in Gp-4 then Gp-3 (507.6 g/kg N⁻¹) and Gp-1 (505 g/kg N⁻¹) whilst the lowest proline was detected in Gp-2 (484.3 g/kg N⁻¹). The serine in the rye flour varied from 237 to 287 g/kg N⁻¹. The highest serine (287 g/kg N⁻¹) was detected in Gp-4 then Gp-2 (264 g/kg N⁻¹) and Gp-3 (261.3 g/kg N⁻¹) whilst the lowest serine was detected in Gp-1 (237 g/kg N⁻¹).

Figure 2. Mean values for the non-essential amino acid contents of different rye flours (g/kg N⁻¹).

Similar findings regarding the arginine, aspartic acid, glycine, tyrosine, alanine, cysteine, glutamic acid, proline and serine contents were noticed by McKevith^[14] who detected that the arginine content in the rye flour is 4.6, 7.2, 4.3, 1.9, 4.3, 3.01, 24.2, 9.4 and 3.8 g/100 g, respectively. Furthermore, another study conducted by Kowieska et al.^[20] presented that the average arginine, aspartic acid, glycine, tyrosine, alanine, cysteine, glutamic acid, proline and serine contents in the rye flour varied from 4.16 to 4.59, 6.13 to 8.18, 3.13 to 6.18, 7.68 to 8.49, 3.75 to 4.30, 1.35 to 1.63, 23.48 to 26.86, 11.1 to 12.2 and 3.85 to 4.38 g/100 g, respectively. Aho and Koivistoinen^[21] also depicted that the average arginine, aspartic acid, glycine, tyrosine, alanine, cysteine, glutamic acid, proline and serine contents in rye flour is 5.07, 7.38, 4.38, 2.38, 3.46, 1.47, 25.98, 11.31 and 3.94 g/100 g N⁻¹. The results are also in agreement with the outcomes of Kihlberg and Ericson^[22] who reported that the arginine, aspartic acid, glycine, tyrosine, alanine, cysteine, glutamic acid, proline and serine contents in rye flour is 4.69, 7.2, 8.2, 1.72, 4.43, 1.43, 26.41, 8.74 and 4.84%, respectively. Similar results are depicted by Rodehutscord et al.^[23] who mentioned that the average arginine, aspartic acid, glycine, tyrosine, alanine, cysteine, glutamic acid, proline and serine contents in the rye flour was between 3.43 to 5.62, 6.48 to 7.32, 4.05 to 4.32, 1.05 to 2.32, 3.82 to 4.21, 1.94 to 2.01, 23.4 to 24.8, 8.27 to 9.68 and 4.54 to 4.78 g/100 g N⁻¹, respectively.

Phenolic contents

The mean value regarding the phenolic content of whole rye flour is shown in Figure 3 The chlorogenic acid in the rye flour varied from 86.7 to 92.43 mg/kg. The maximum chlorogenic acid (92.43 mg/kg) was detected in Gp-2 then Gp-1 (91.4 mg/kg) and Gp-4 (90.76 mg/kg), While, in Gp-3 (86.7 mg/kg) minimum chlorogenic acid was present. These current results agree with the outcomes of Andreasen et al.^[24] who studied ferulic acid and phenolic acids in seventeen rye varieties. Heiniö et al.^[25] also mentioned similar findings while investigating quantities of phenolic compounds in the different rye varieties. Whereas the p-coumaric acid in the rye flour varied from 2.7 to 5.4 mg/kg. The maximum p-coumaric acid (5.4 mg/kg) was detected in Gp-1 then Gp-4 (3.6 mg/kg) and Gp-3 (3.5 mg/kg). While the Gp-2 (2.7 mg/kg) elucidated minimum p-coumaric acid content. Nystrom et al.^[26] detected similar results and reported that p-coumaric acid in the whole rye flour is 3.3 mg/100 g. These outcomes are also in line with Bondia-Pons et al.^[27] and Andreasen et al.^[24] documented that p-coumaric acid in the rye flour varied from 37–65 μg/g dry mass. While the gallic acid in the rye flour ranged from 64.7 to 97.1 mg/kg. The maximum gallic acid (97.1 mg/kg) was detected in Gp-4 then Gp-1 (78.5 mg/kg) and Gp-2 (69.3 mg/kg). While the Gp-3 (64.7 mg/kg) showed minimum gallic acid content. However, the caffeic acid in the rye flour varied from 16.9 to 25.9 mg/kg. The maximum caffeic acid (25.9 mg/kg) was detected in Gp-2 then Gp-1 (21.4 mg/kg) and Gp-3 (16.9 mg/kg). In Gp-4 (20 mg/kg) minimum, caffeic acid content was detected. Mattila et al.^[18] explored that caffeic acid in the whole rye flour is 1 mg/100 g. Whereas, another study carried out by Bondia-Pons et al.^[27] depicted similar results. Whereas the coumaric acid in the rye flour varied from 218.1 to 228.4 mg/kg. The maximum p-coumaric acid (228.4 mg/kg) was detected in Gp-2 then Gp-3 (223 mg/kg) and Gp-1 (220 mg/kg). While the Gp-4 (218.1 mg/kg) explored minimum p-coumaric acid content.

Figure 3. Mean values for the phenolic content of different rye flours (mg/kg).

Vitamins

Mean values regarding the vitamin contents of rye flour is shown in Figure 4. Thiamin in the rye flour varied from 239.7 to 252.3 μg/100 g. The maximum thiamin (252.33 μg/100 g) was detected in Gp-2 then Gp-1 (248 μg/100 g) and Gp-4 (247.7 μg/100 g) while, minimum thiamin was detected in Gp-3 (239.7 μg/100 g). Whereas the riboflavin in the rye flour varied from 76.7 to 84.4 μg/100 g. The highest riboflavin (84.4 μg/100 g) was detected in Gp-1 then Gp-4 (84 μg/100 g) and Gp-2 (81.3 μg/100 g) while, the lowest riboflavin was detected in Gp-3 (76.7 μg/100 g). Moreover, the niacin in the rye flour varied from 379.7 to 397 μg/100 g. The highest niacin (397 μg/100 g) was detected in Gp-2 then Gp-3 (388 μg/100 g) and Gp-4 (380 μg/100 g) while, the lowest niacin was detected in Gp-1 (379.7 μg/100 g).

Figure 4. Mean values for the vitamin content of the different rye flour (μg/100 g).

The pantothenic acid in the rye flour varied from 241.4 to 246.7 μg/100 g. The maximum pantothenic acid (246.7 μg/100 g) was detected in Gp-3 then Gp-4 (242.7 μg/100 g) and Gp-1 (241.4 μg/100 g) whilst, minimum pantothenic acid was detected in Gp-2 (241 μg/100 g). Whereas the pyridoxine in the rye flour varied from 89.34 to 99 μg/100 g. The highest pyridoxine (99 μg/100 g) was detected in Gp-2 then Gp-1 (94.34 μg/100 g) and Gp-4 (90 μg/100 g) whilst, the lowest pyridoxine was detected in Gp-3 (89.34 μg/100 g). The folate in the rye flour varied from 13 to 24.4 μg/100 g. The maximum folate (24.4 μg/100 g) was detected in Gp-4 then Gp-2 (21.4 μg/100 g) and Gp-1 (18 μg/100 g) whilst, minimum folate was detected in Gp-3 (13 μg/100 g). The ascorbic acid in the rye flour varied from 240 to 470 μg/100 g. The highest ascorbic acid (470 μg/100 g) was detected in Gp-3 then Gp-2 (440 μg/100 g) and Gp-4 (270 μg/100 g) whilst, the lowest ascorbic acid was detected in Gp-1 (240 μg/100 g). These results are in line with the outcomes of Németh and Tömösközi,^[28] who reported that the average thiamin, riboflavin, niacin, pantothenic acid, pyridoxine, and folate content in the rye flour varied from 4.0–4.6, 1.8–1.9, 12–15, 10–14, 3–3.5 and 0.48–0.51 mg/kg, respectively. A study conducted by the Mihhalevski et al.^[6] mentioned that the thiamin, niacin, pantothenic acid, pyridoxine, riboflavin and folate content in rye flour ranges from 246–284, 191–289, 234–241, 82–105, 82–91 and 72–87 μg/100 g of dry matter (DM), respectively.

Lignin content

The mean value regarding lignin contents of rye flour has been shown in Figure 5. The matairesinol in the rye flour varied from 27 to 33.5 μg/100 g. The maximum matairesinol (33.5 μg/100 g) was detected in Gp-2; the minimum matairesinol was detected in Gp-1 (27 μg/100 g). Whereas the secoisolariciresinol in the rye flour varied from 30.1 to 38.2 μg/100 g. The maximum secoisolariciresinol (38.2 μg/100 g) was detected in Gp-1 while, the minimum secoisolariciresinol (27 μg/100 g) was detected in Gp-4. Whilst the range of syringaresinol in the rye flour is 830 to 847 μg/100 g. The maximum syringaresinol (847 μg/100 g) was detected in Gp-2 while, the minimum syringaresinol (830 μg/100 g) was detected in Gp-1. However, the range of pinoresinol in the rye flour is 381.3 to 396 μg/100 g. The maximum pinoresinol (396 μg/100 g) was detected in Gp-1 while the minimum pinoresinol (381.3 μg/100 g) was detected in Gp-3. Whereas the medioresinol in the rye flour varied from 142.1 to 151 μg/100 g. The maximum medioresinol (151 μg/100 g) was detected in Gp-3 and the minimum medioresinol (142.1 μg/100 g) was detected in Gp-2. The range of lariciresinol in the rye flour is 321.3 to 329.6 μg/100 g. The maximum lariciresinol (329.6 μg/100 g) was detected in Gp-2 while, the minimum lariciresinol (321.3 μg/100 g) was detected in Gp-4. Whereas the isolariciresinol in the rye flour varied from 110 to 129 μg/100 g. The maximum isolariciresinol (129 μg/100 g) was detected in Gp-1 and the minimum isolariciresinol (110 μg/100 g) was detected in Gp-3. The present findings are in line with the results elucidated by the Penalvo et al.^[29] reported that secoisolariciresinol, pinoresinol, syringaresinol, medioresinol, matairesinol, lariciresinol and isolariciresinol in the whole grain rye flour are 973, 381, 324, 148 and 27 μg/100 g, respectively. Another study concluded by Heiniö et al.^[25] the study of different lignans present in whole rye flour mentioned that matairesinol, secoisolariciresinol, syringaresinol, pinoresinol, and lariciresinol are 32.4, 36.2, 1770.6, 179.1 and 146.8 μg/100 g, respectively.

Figure 5. Mean values for the lignin content (μg/100 g) of the different rye flour. Mat, matairesinol; Seco, secoisolariciresinol; Syr, syringaresinol; Pin, pinoresinol; Lar, lariciresinol; Isolari, isolariciresinol.

Alkylresorcinols contents

Mean values regarding alkylresorcinols contents of rye flour have been shown in Figure 6. The results presented that the C17:0 in the rye flour varied from 19.4 to 30.4 mg/100 g. The maximum C17:0 (30.4 mg/100 g) was detected in Gp-2 whilst, the minimum C17:0 was detected in Gp-3 (19.4 mg/100 g). Whereas the C19:1 range from 1.7 to 5.5 mg/100 g. The maximum C19:1 (5.5 mg/100 g) was detected in Gp-2 while, the minimum C19:1 was detected in Gp-4 (1.7 mg/100 g). However, the C19:0 in the rye flour varied from 27 to 39 mg/100 g. The maximum C19:0 (39 mg/100 g) was detected in Gp-2 whilst, the minimum C19:0 was detected in Gp-4 (27 mg/100 g). However, C21:0 varied from 22 to 35 mg/100 g in the rye flour. The maximum C21:0 (35 mg/100 g) was detected in Gp-2 whilst, the minimum (22 mg/100 g) C21:0 was detected in Gp-3. While C23:0 varied from 11 to 24 mg/100 g. The maximum C23:0 (24 mg/100 g) was detected in Gp-2 whilst, the minimum (11 mg/100 g) C23:0 was detected in Gp-4. The range of C25:0 is 9 to 17 mg/100 g. The maximum C25:0 (17 mg/100 g) was detected in Gp-1 whilst, the minimum (9 mg/100 g) C25:0 was detected in Gp-3. Alkylresorcinols are mostly present in rye and therefore are known to give this cereal a distinct taste. Alkylresorcinols, lignans, and phenolic acids contribute significantly to the total phenolics in rye flour and have significant antioxidant properties.^[30] These results are by the study of Mattila et al.^[18] who explored the C17:0, C19:1, C19:0, C21:0, C23:0 and C25:0 in the whole rye grain flour is 24, 0.3, 26, 18, 11 and 7 mg/100 g, respectively. Another study by Ross et al.^[31] presented that whole grain rye flour contains 19, 27, 22, 10 and 9 mg/100 g of C17:0, C19:0, C21:0, C23:0 and C25:0, respectively. Chen et al.^[32] also explored that the C17:0, C19:0, C21:0, C23:0 and C25:0 are 23, 32, 26, 11 and 8 mg/100 g in the whole rye flour. Similar results are noticed by Heiniö et al.^[25] elucidated that the C17:0, C19:0, C19:1, C21:0, C23:0 and C25:0 are present at 35.3, 4.5, 38.1, 29.3, 17.4 and 14.8 mg/100 g, respectively in the rye flour.

Figure 6. Mean values for the alkylresorcinols content (mg/100 g) of the different rye flour.

Conclusion

The results showed that rye flour is a significant source of phenolic chemicals, alkylresorcinols, vitamin B complex, and both essential and non-essential amino acids. GP-2 is the most nutritionally robust of the four rye varieties that were evaluated (GP-1, Gp-2, Gp-3, and Gp-4). It has higher levels of vitamins, amino acids, and other bioactive components. Gp-2 is a better option than other alternatives because of its improved nutritional profile. The remarkable nutritional richness of rye flour accentuates its potential for enhancing the nutritional and functional attributes of diverse food products. Consequently, incorporating rye flour into various food formulations holds promise for elevating their overall nutritional value and functional benefits.

Informed consent statement

Consumers’ consent was not required.

Acknowledgments

This work was supported by the Department of Food Sciences and HITECH lab Government College University Faisalabad, Pakistan. The researchers would like to thank all the affiliated institutes for their kind support for the publication of this project.

Disclosure statement

No potential conflict of interest was reported by the author(s).

Data availability statement

Data is contained within the article.

Additional information

Funding

This work was supported by the The corresponding Author is from low income country..