Fructosyl transferase and hydrolase activities in rhizophores and tuberous roots upon growth of Polymnia sonchifolia (Asteraceae)

Abstract

The underground reserve organs of yacon (Polymnia sonchifolia Poep. Endl.), similarly to other economically important Asteraceae, accumulate more than 60%, on a DW basis, of inulin type β(2‐1) fructans, mainly oligomers (GF2–GF16). Although sucrose:sucrose 1‐fructosyl transferase (1‐SST), fructan:fructan 1‐fructosyl transferase (1‐FFT) and fructan 1‐exohydrolase (1‐FEH) were properly described and characterized from a number of plant species, detailed information about their activities in different organs during development are rather scarce in the literature. In the present work 1‐SST, 1‐FFT and 1‐FEH activities were measured monthly in rhizophores and tuberous roots of yacon plants during their complete growth cycle under field conditions. Results showed that 1‐SST activity in rhizophores was always higher than 1‐FFT activity and increased up to 8 months of cultivation, decreasing to initial values at the end of the growth period. In the tuberous roots 1‐SST activity was also higher than 1‐FFT but varied differently. The higher values were found at the beginning of tuberization (3‐month‐old plants) and at the flowering phase (7‐month‐old plants). Results also showed that synthesizing activities in yacon plants were always higher in rhizophores than in the tuberous roots, while hydrolysing activity predominated in the latter, mainly when 1‐kestose and nystose were used as substrates. 1‐FEH from yacon plants showed low efficiency when commercial inulin from Helianthus tuberosus was utilized as substrate. The analysis of the enzymatic activities performed during growth of yacon clearly indicated the most appropriate source organ and phase of development to obtain the highest enzymatic activities for purification purposes and for the production of fructo‐oligosaccharides (FOS). Furthermore, the results suggested that the relative levels of activities of 1‐SST, 1‐FFT and 1‐FEH could be involved in the chain length distribution of the fructan molecules found in rhizophores and in tuberous roots of this species.

Yacon [Smallanthus sonchifolia (Poepp. et Endl.) H. Robinson] chemical composition and use - a review

“…The tuberous roots contain only 0.3-3.7% protein (Table 1), but 70-80% of dry matter is composed of saccharides, mainly fructooligosaccharides (Goto et al 1995). The underground storage organs of yacon accumulate over 60% (on dry basis) of inulin type β (2→1) fructans, mainly oligomers (GF 2 -GF 16 ) (Itaya et al 2002). The structures of kestose and nystose, the main fructooligosaccharides, are given in Figure 2.…”

“…Itaya et al (2002) investigated the activities of the enzymes sucrose 1-fructosyl transferase, fructan:fructan 1-fructosyl transferase and fructan 1-exohydrolase in rhizophores and tuberous roots of yacon plants during their complete growth cycle under field conditions. The higher values were found at the beginning of tuberisation (3-months old plants) and at the flowering phase (7-months old plants).…”

Effects of Dietary Supplementation of Yacon(Polymnia sonchifolia) By-products and Pine Needle Powder on Growth Performance and Meat Quality of Chicken Thigh Meat

“…야콘에는 식물성 섬유소가 많으며, 미네랄 특히 칼륨을 많이 포함하고 있어서 체내 나트륨 양의 균형 을 맞춰 혈압을 낮추는 효과를 나타내고, 칼슘, 마그네슘 등 도 풍부해 골다공증 예방에도 효과가 있으며, 혈청 콜레스 테롤 등을 감소시켜 체질 개선에 도움이 되는 것으로 보고 되고 있다 (Kim et al, 2010;Lee et al, 2002). 야콘에는 프락 토올리고당이 다량 함유되어 있으며, 프락토올리고당은 위 장관에서 흡수되지 않기 때문에 비만증, 동맥경화, 당뇨병 등에 효과적이며, 위산과 소화효소에 의해 분해되지 않고 대 장에 도달하여 장내 비피더스균만이 선택적으로 이용되어 유해균을 억제하는 것으로 알려져 있다 (Itaya et al, 2002).…”

Effects of Dietary Supplementation of Yacon By-products and Mugwort Powder on Carcass Characteristics and Meat Quality of Chicken Thigh Meat

“…야콘에는 칼륨을 많이 함유하고 있어 체내 나 트륨 양의 균형을 맞추어 혈압을 낮추는 효과를 나타내고, 칼슘, 마그네슘 등도 풍부해 골다공증 예방에도 효과가 있 다 (Kim et al, 2010;Lee et al, 2002). 그리고 야콘에 다량 함유되어 있는 프락토올리고당은 위나 장에서 흡수되지 않 기 때문에 비만, 동맥경화, 당뇨병 등에 효과적이며, 위산과 소화 효소에 의해 분해되지 않고 대장에 도달하여 유해균의 생육을 억제하는 것으로 알려져 있다 (Itaya et al, 2002).…”