Saccharide and Fructooligosaccharide Contents, and Invertase, 1-KHE, 1-SST, 1-FFT and 6G-FFT Activities in Green Asparagus Spears during Storage: Effects of Temperature and Spear Portion

Abstract

Unlike most vegetable crops, asparagus, a hardy perennial plant, is commonly consumed and appreciated because it is low in calories and provides substantial amounts of reducing sugars and a very low amount of fructooligosaccharides (FOS), and these fructosyl polymers are well known for their health benefits.1) The chemical characteristics of the spears are markedly affected by temperature, 2) growth conditions 3) and harvest date. 4) Carbohydrates are major constituents of asparagus spears and contribute considerably to their quality.1) The main carbohydrates in asparagus spears are glucose, fructose and sucrose, 2,4) while the presence of FOS has never been reported. In asparagus carbohydrates are translocated from storage roots to spears, where they are hydrolyzed into hexoses and used during the catabolic activities of the spears.4) Thus, soluble carbohydrate levels decline particularly during the first hours after harvest, and this decline triggers deterioration in the spears. 5,6) While little FOS are detected in aerial parts of asparagus, it remains still unclear the reason for the difference of FOS content between the top and the bottom parts of the spears. On the other hand, the role of FOS in spears tissues is also unknown. It is not clear if their presence results from simple translocation from roots to spears to provide energetic substrates, or whether they are translocated to play specific roles such as osmoregulation, or to partially compensate for the rapid decline of sucrose in tips. Numerous investigations have been carried out on the structures, 7 11) enzymology 12) and molecular biology 13) of FOS in roots of asparagus and such research works were recently reviewed by Shiomi et al.,14) but there have been no reports on their presence in aerial tissues. Although many studies have focused on the carbohydrate content of edible spears after harvesting, few studies have focused on soluble and reducing sugars, including soluble invertase, while no investigations have been carried out on FOS and their metabolizing enzymes in asparagus spears.From the technological point of view, freshly harvested spears deteriorate rapidly at ambient temperatures, 1) and have a short shelf life, which is strongly related to respiratory activity.15) This postharvest deterioration is accompanied by biochemical changes, particularly in spear tips J. Appl. Glycosci., 54, 187 194 (2007) Abstract: Fresh spears of asparagus were stored in the dark at 4, 10 or 20 C for 2 weeks. During storage contents of glucose, fructose, sucrose, 1-kestose, neokestose and nystose, and activities of invertase, 1-kestose hydrolyzing enzyme (1-KHE), sucrose: sucrose 1-fructosyltransferase (1-SST), fructan: fructan 1-fructosyltransferase (1-FFT) and fructan: fructan 6 G -fructosyltransferase (6G-FFT) were determined in the top, middle and bottom portions of the spears. A gradient was observed, from the bottom to the top, for glucose, fructose and sucrose which constitute the major proportion of carbohydrates, while fructooligosaccharides, ne...

Effect of the extraction method on phytochemical composition and antioxidant activity of high dietary fibre powders obtained from asparagus by-products

“…The highest content was found in fibres obtained after intense treatment with ethanol (I/E), with the rest of the fibres having almost the same fructan content. Fructans present in asparagus were mainly fructooligosaccharides (FOS -with low polymerisation degree) instead of inulin (high molecular weight) (Shiomi et al, 2007). FOS content of asparagus by-product was around 4 mg/g of dry weight (data not shown) and during the fibre obtaining process, it decreased between 25% and 95%, a reduction that was explained by the high solubility of these low molecular weight carbohydrates (3-4 polymerisation degree) in water/ethanol mixtures, even at room temperature.…”

Food Biochemical Study on Fructans and Related Synthesis Enzymes

“…They also showed the metabolizing enzymes of these fructo oligosaccharides play a role in the balance of sugars between the bottom and the top of the spears where high catabolic activities were observed. 48) These results suggest that high fructo oligosaccharede content in asparagus spears may extend the rapid decline of sugars in the top portion. …”

“…40) However, nothing has been reported for the metabolism of fructo oligosaccharides except the work of Shiomi et al . 48) The results showed that only short chain fructo oligosaccharides (1 kestose and nystose) are present and their contents in the spears is very low compared to those of glucose, fructose and sucrose. They also showed the metabolizing enzymes of these fructo oligosaccharides play a role in the balance of sugars between the bottom and the top of the spears where high catabolic activities were observed.…”

THE EFFECT OF STORAGE AND BOILING TIME OF YACON TUBERS TO SCFA AND LACTIC ACID CONCENTRATIONS BY Bifidobacteriumlongum Reuter ATCC 15707 AND Lactobacillus acidophilus IFO 13951

“…Based on the water content of samples and HPLC chromatogram, consentration of FOS and saccharides yacon tubers samples can be identified, as showed in There was a research finding that, after 12 days of shade storage, FOS concentration of yacon tubers were decreased from 50-62 to 27-37% of dry weight, while the concentration of saccharides increased from 29-34 to 48-52%. During the six days sunlight exposure, FOS concentrations were decreased from 50-62 to 29-44% and saccharides increased from 29-34 to 45-51% of dry weight 17 .…”