Vol.:(0123456789) 1 3 Journal of Food Measurement and Characterization https://doi.org/10.1007/s11694-020-00624-9 ORIGINAL PAPER Morphological, functional and thermal characteristics of hydroxypropylated‑crosslinked barley starches Tooba Mehfooz 1  · Tahira Mohsin Ali 1  · Maria Ahsan 1  · Sana Abdullah 1  · Abid Hasnain 1 Received: 10 April 2020 / Accepted: 26 August 2020 © Springer Science+Business Media, LLC, part of Springer Nature 2020 Abstract The present study investigated efects of three diferent levels of crosslinking using a mixture of sodium trimetaphosphate (STMP) and sodium tripolyphosphate (STPP) on hydroxypropylated barley starches. Hydroxypropylated barley starches crosslinked with 1%, 1.5% and 2% mixture of STMP and STPP were coded as HPCL (1) , HPCL (1.5) and HPCL (2.0) , respec- tively. However, the level of hydroxypropylation employed was same for all the modifcations i.e. 6%. The results showed that increase in level of crosslinking increased swelling power, solubility and water holding capacity of starches. HPCL (2.0) starch demonstrated noticeably lower percent transmittance, higher percent retrogradation and elevated peak viscosity. Harder gels were produced by dual modifed barley starches. A decline was observed in thermal transition temperatures after dual modifcation. FTIR was unable to detect much diference among diferent samples. However, peak at 1414 cm −1 associated with hydroxypropylation was detected. Hydroxypropylation followed by crosslinking led to roughness and grooves formation on the surface of barley starch granules. Keywords Barley starch · Dual modifcation · Hydroxypropylated distarch phosphate Introduction Among diferent cereal crops barley (Hordeum vulgare) has its own unique importance. It is used as a source of food in many parts of the world. Like other grains, barley has majorly 70% carbohydrate. Apart from starch isola- tion from cereal grains, proper utilization of remnants is equally important too. The leftovers after processing are termed as by-products of food or food wastes which could contain valuable functional components. The remnants of fruits and vegetables yield phenols, carotenoids, dietary fbers etc. while cereal waste generates fbers, Similarly, roots and tuber waste helps in the recovery of organic acids and phenols [1]. Such wastes are treated these days in order to achieve nutraceutical components that act as functional ingredients in food products [2]. The main purpose of devel- opment of functional food is prevention from disease and maintaining a healthy body. Exploitation of undervalued components after principle isolation/extraction is governed by “5 Stage Universal Recovery Processing” that explains the whole process form macroscopic pre-treatment to till product formation or encapsulation in fve steps namely: (1) macroscopic pre-treatment (2) macro- and micromol- ecules separation, (3) extraction, (4) isolation-purifcation (5) product formation [3]. In case of barley, husk that is left after starch extraction is loaded with insoluble fbers that are potentially helpful for intestinal health. Though barley has been known for the production of malt and extraction of betaglucan, but it can also be used for the isolation of a value-added product with diversifed uses in food industries i.e. “starch”. After isolation of starch, there are some constraints in the use of natural/raw (unmodifed) barley starch commercially. It is due to native starch’s irresistibility against shear and acidic conditions. To overcome these issues, modifcation * Tooba Mehfooz toobamehfooz@gmail.com Tahira Mohsin Ali tahira.mohsin@uok.edu.pk Maria Ahsan s.maria.ahsan@gmail.com Sana Abdullah sanabdullah92@gmail.com Abid Hasnain abidhasnain@uok.edu.pk 1 Department of Food Science and Technology, University of Karachi, Karachi 75270, Pakistan