In the recent years, health benefits of dietary fibre in reducing the risk of many chronic diseases have extensively been addressed (Venn and Mann, 2004; Streppel et al., 2008; Aune et al., 2011; Jurasová et al., 2011). Epidemiological and interventional studies reported that consumption of dietary fibre rich foods such as vegetables, fruits, and whole grains reduce the blood cholesterol, especially, low-density lipoprotein and blood pressure, promote weight loss and improve insulin sensitivity (Anderson, 2003; Streppel et al., 2008; Ivanišová et al., 2017; Rana et al., 2019). Diet implicates the etiology of diabetes and fibre rich diets have low glycemic index and, thus, decrease diabetic incidence (Meyer et al., 2000; Murtaugh et al., 2003; Venn and Mann, 2004; Kaline et al., 2007; Krishnan et al., 2007). Dietary fibre also reduce insulin need, slow down the absorption of sugar and prevent spikes after meals (Takekawa and Matsumoto, 2012; Kamila et al., 2018). Risk of cancers incidence, particularly colon cancer, has also been reported to cut to those who consume high dietary fibre containing foods (Aune et al., 2011; Dong and Qin, 2011; Alam et al., 2017a, b). Intake of high fibre diets also help alleviate constipation (Dhingra et al., 2012; Stewart and Schroeder, 2013). Soluble fibre has been reported to improve immunity, to speed up elimination of toxic waste through the colon and to enhance digestion. They can help treat or prevent overweight or obesity (Takekawa and Matsumoto, 2012; Kamila et al., 2018).

Data on dietary fibre are sparse. Bangladesh does not yet have its own dietary fibre data; some data are being generated for a few common foods. Dietary fibre data for ethnic or unconventional foods have not yet been generated or reported elsewhere. In our present-attempt to prepare a food composition database for Bangladesh with special reference to ethnic foods (Islam et al., 2010; Islam et al., 2012; Shajib et al., 2013; Alam et al., 2016; Alam et al., 2019; Hossain et al., 2016; Islam et al., 2016; Rana et al., 2019), this article reports the analysis of total dietary fibre (TDF) for sixty-nine vegetables and fruits of ethnic and unconventional varieties. Data generated in present study would surely add to and enrich the existing Food Composition Tables and database for Bangladesh (Islam et al., 2010; Islam et al., 2012; Shaheen et al., 2014).

Table 3 and Table 4 represent the total dietary fibre contents in the ethnic leafy and non-leafy vegetables and Table 5 and Table 6 represent the total dietary fibre contents in the ethnic fruits, and unconventional leafy and non-leafy vegetables. In the ethnic vegetables, the dietary fibre ranged from 1.02 ±0.16 to 7.16 ±0.16 g per 100 g fresh edible portion (pooled mean ±SD: 2.25 ±1.34) for leafy vegetables (Table 3), 0.18 ±0.01 to 6.71 ±0.49 g per 100 g fresh edible portion (pooled mean ±SD: 2.75 ±1.64) for non-leafy vegetables (Table 4) and in the ethnic fruits (Table 5), the content varied from 1.21 ±0.12 to 5.29 ±0.20 g per 100 g fresh edible portion (pooled mean ±SD: 3.11 ±1.44). Although the combined data for ethnic fruits showed high amount of dietary fibre compared to ethnic leafy- and nonleafy vegetables, but we did not observe any statistical significance. In unconventional vegetables (Table 6), the content ranged from 3.08 ±0.34 to 7.75 ±0.13 g per 100 g fresh edible portion (pooled mean ±SD: 5.79 ±1.42) for leafy vegetable and 1.02 ±0.06 to 8.82 ±0.40 g per 100 g fresh edible portion (pooled mean ±SD: 4.93 ±3.29) for nonleafy vegetable. Like ethnic vegetables and fruits combined data, unconventional vegetables also failed to show statistical significance between leafy and non-leafy vegetables.

The present study indicates that amongst the vegetables and fruits those were tested, Orohordal contains the highest amount of total dietary fibre (8.82 ±0.40 g per 100 g fresh edible portion).

It was followed by Chimtishak, Telakucha, Betgach, Gondhobatali, Muktajhuri, Orhorpata, Oraibalai, Roktodrone, Tetulpata, Bondhonia, Sornolota, which also contain rich amount of dietary fibre ranging from 7.75 ±0.13 to 6.12 ±0.36 g per 100 g fresh edible portion. The other vegetables such as Jolpaipata, Jonglaam, Jamalu, Missayanu, Shimeful, Mulachi, Bonpalong, Titbegun, Vennapata, Rosko, Betagi, Kochi aampata, Sakumubakla also contain a high amount of TDF (5.74 ±0.06 to 4.06 ±0.30 g per 100 g fresh edible portion). For leafy vegetable, the lowest TDF was present in Simeialupata (1.02 ±0.16 g per 100 g fresh edible portion). Among the fruits, Jongliaam or Bonaam has the highest amount of TDF (5.29 ±0.20 g per 100 g fresh edible portion), followed by Rosko (4.38 ±0.46 g per 100 g fresh edible portion) and Jonglikola (3.06 ±0.09 g per 100 g fresh edible portion). The study findings also indicate that the unconventional vegetables contain higher amount of total dietary fibre (5.65 ±1.85 g per 100 g fresh edible portion) as compared to the ethnic vegetables (2.52 ±1.48 g per 100 g fresh edible portion). In case of most food items, the content of dietary fibre in ethnic vegetables was found to be, somewhat, comparable to that of commonly consumed vegetables in Bangladesh (Islam et al., 2010; Islam et al., 2012; Shaheen et al., 2014; Alam et al., 2016; Rana et al., 2019) as well as in India (Longvah et al., 2017) and elsewhere (Dhingra et al., 2012). From Table 5 it can be seen that, among ethnic fruits, Rosko, which looks like Plum or Black berry, was found to contain much higher amount of dietary fibre (4.38 g per 100 g edible fresh) than the Plum (2.80 g per 100 g edible fresh) or higher than or similar to the Black berry (3.50 or 4.35 g per 100 g fresh edible portion) (Islam et al., 2012; Longvah et al., 2017).

Similarly, Jongliaam and Joglikola were found to contain higher amount of dietary fibre (5.29 and 3.06 g per 100 g fresh edible portion respectively) as compared to the mango (3.65 or 1.5 g per 100 g fresh edible portion) and banana (1.90 or 2.6 g per 100 g fresh edible portion) (Islam et al., 2010; Islam et al., 2012; Shaheen et al., 2014).

In the ethnic Mulachi and Green Chilli, the total dietary fibre was found to be almost same (4.74 vs 4.90 g per 100 g fresh edible portion). The recommended dietary intake (RDI) of TDF for an adult human is 30 – 38 g per day and the consumption of these ethnic and unconventional vegetables and fruits can contribute up to 30% of RDI of TDF.

Some of ethnic vegetable and fruits such as Gondhobatali, Oraibalai, Shimeful, Rosko, Betagi, Kochi aampata, Jongliaam and most of the unconventional vegetables were found to contain rich amount of total dietary fibre. The findings of present study would encourage people to adapt dietary diversity. Cultivation and regular intake of plant foods rich in fibre might reduce the risk of many diseases. It would also go a long way in filling up the data gap that exists in food composition database for Bangladesh.