Fructans from Non-differentiated Garlic (Allium sativum): Extraction, Characterization, and Possible Applications

Garlic (Allium sativum) is one of the 20 principal vegetables cultivated around the world due to its culinary attributes and medical properties, some of which are because of its high fructan content. During plant development, temperature and photoperiod can affect bulb quality. One of the main defects presented in the field is the no or low formation of cloves, producing bulbs with a soft consistency and appearance that cannot serve as a “seed” for the next crop generation. These plants have no commercial value and this defect can reduce yeilds by 50%. This problem could be related to fructans biosynthesis, which are fructose polymers linked by b bonds that present different polymerization degrees depending on the physiological stage of the plant. Fructans have an important agro-industrial quality for their different functional and nutritional properties. The aim of this work was to extract and characterize fructans from non-differentiated garlic (NDG) that could be an important source of this type of oligosaccharides. Fructans from NDG harvest 2013-14 were extracted and compared with fructans from differentiat garlic (DG), white onion (WO), and commercial inulin (CI). Samples were used to quantify reducing sugars (RS), fructan content, and polymerization degree (DP), along with the carbohydrate profile by thin-layer chromatography (TLC). Water absorption index (WAI) and oil absorption capacity (OAC) of fructans were also determined. WO had the highest content (4.82%) of RS, and CI had the lowest content (1.41%). Fructan content was similar between DG (96.65%) and CI (97.18%); WO had 22.32%, NDGNDG had 82.33% of fructan content. DP varied considerably from 2 for WO to 23 for CI; DP for NDG was significantly lower (8) than NG (13). These differences were observed on TLC. Results shown that fructans from NDG can absorb more than 40% of weight in water; meanwhile, results from OAC show that DG and NDG have the same capacity (2.54 g/g and 2.50 g/g respectively). Results indicate that non-differentiated garlic has agro-industrial potential for its fructan content and DP could be used as fat replacement stabilizers or texturizing agents.