Physicochemical Properties of Bamboo Shoots of Selected Species grown in Kenya and Utilization as Human Food

Abstract

A survey on consumption of bamboo shoots was carried out in Mt. Elgon and Nairobi regions to establish the status of utilizing the shoots as food. Three species namely Dendrocalamus giganteus, Bambusa vulgaris and Yushania alpina were analyzed for some physicochemical properties. To determine the best part of the shoot to consume, the shoot of Y. alpina was divided into upper (15 cm from the apex) and lower portions and the content of physicochemical constituents determined separately in the two portions. The effect of traditional processing techniques on quality was carried out by boiling shoots of B. vulgaris in 1, 2 and 5% ash of bean stalks and NaCl solutions for 10, 30 and 60 min. Products made with bamboo shoots were evaluated for consumer acceptance using 7 and 9-point hedonic scales. Results of the survey showed that all interviewees had consumed the shoots of Y. alpina, 37.5% of restaurants in Nairobi sold bamboo shoots, and 62.5% of the hotels sold less than 0.5 kg per week by 62.5%. Composition (%g/100gfwb) of the three species showed carbohydrates of 1.9-3.6%, protein of 2.3-2.6% and ash content of 0.98-1.17%, with potassium content of 288.8-362.6mg/100g. D. giganteus and B. vulgaris contained up to 288.8mg/100g total flavonoids compared to 53.14mg/100g in Y. alpina. Y. alpina was found to contain on dry weight basis carbohydrates and fibre contents of 23.6 and 23.9% respectively in the upper compared to 17.3 and 30.7% respectively in the lower portion. K content of 3,590mg/100gdwb in the upper and 2,760mg/100gdwb in the lower portion was also observed. Boiling shoots of B. vulgaris in 2-5% NaCl solution for 60 min was found to reduce fibre content (dwb) from 29.4 to 7.7-8.8% compared to ash which reduced it to 21.2-24.4 %. Similarly, K content reduced from 4,000 to 2,000mg/100g in NaCl solution but rose to 3600-10,000mg/100g in shoots boiled in 2-5% ash. Both NaCl and ash were effective in reducing anti-nutrients with ash causing up to 70% reduction after only 10 min. On products, fried shoots were rated “like” whereas cookies made with 200 g purees of shoots scored “like very much” compared with those with 100g which were rated “like moderately”. Porridge and biscuits with shoots powder higher than 5% were not acceptable to consumers due to bitterness. These findings shows that business in bamboo shoots as human food is low but has potential to grow and produce processed foods of high consumer acceptance by Kenyans.