Contents lists available at ScienceDirect Food Research International journal homepage: www.elsevier.com/locate/foodres Review Solid state fermentation of de-oiled rice bran: Effect on in vitro protein digestibility, fatty acid profile and anti-nutritional factors Amit Ranjan ⁎ , Narottam Prasad Sahu, Ashutosh Dharmendra Deo, Sarvendra Kumar Fish Nutrition, Biochemistry and Physiology Division, ICAR- Central Institute Of Fisheries Education, off Yari Road, Panch Marg, Versova, Mumbai 400061,India ARTICLE INFO Keywords: Deoiled Rice Bran (DORB) Rhizopus oryzae Solid state fermentation Phytate Trypsin inhibitor ABSTRACT An experiment was conducted to study the effect of solid state fermentation of de-oiled rice bran (DORB) with Rhizopus oryzae on in vitro protein digestibility, anti-nutritional factors and fatty acid profile. The fermentation of DORB with Rhizopus oryzae significantly reduced the in vitro protein digestibility of DORB (p < .05). The fermentation of DORB with Rhizopus oryzae increased the saturated fatty acid (SFA) content by 46.83%, while decreased the MUFA and PUFA contents by 14.01 and 8.76%, respectively. The n-6 fatty acid content of FDORB increased by 6.19%, while n-3 fatty acid content decreased by 53.92%. The fermentation of DORB resulted in significant reduction in phytate and trypsin inhibitor activity (p < .05). Based on the present result it is con- cluded that the fermentation of DORB with Rhizopus oryzae improves the n-6 fatty acid profile and brings sig- nificant reduction in the phyate and trypsin inhibitor content but fails to improve the in vitro protein digest- ibility and hence cannot be recommended as a suitable microbe for DORB fermentation. 1. Introduction De-oiled rice bran (DORB) is an agro-industrial residue, which is most commonly used ingredient in the diets of cattle, poultry and fish (Silveira & Badiale-Furlong, 2009; Ranjan et al., 2018). Agro-industrial residues are generally considered the best substrates for the solid state fermentation (SSF) processes. SSF had been used to add value to the raw materials (Kang, Park, Lee, Hong, & Kim, 2004; Singhania, Patel, Soccol, & Pandey, 2009). SSF has been reported to enhance the nutri- tional quality of agro-industrial products that can be used in animal and aquafeed industries (Imelda- & Paulraj, 2003; Vijayakumar, 2003). SSF method is also useful in improving the nutrient digestibility (Cho et al., 2007; Kim, Lohakare, Yun, Heo, & Chae, 2007; Vidotti, Carneiro, & Viegas, 2002) and enriching the quality of protein (Oduguwa, Edema, & Ayeni, 2008). Hence, Solid state fermentation (SSF) technology is very useful and found suitable to increase the nutrient contents and their bio-availability, thus adding the value to the product and creating new opportunities for their utilization. Many microorganisms are capable of growing on solid substrates, especially filamentous fungi, can grow to a significant extent in the absence of free water (Chahal, 1985; Gao et al., 2008). Rhizopus oryzae is a rapidly growing fungus which propagates by hydrophobic sporangiospores that readily disperse after maturation and also identified as generally regarded as safe (GRAS) by USFDA. Hence, Rhizopus oryzae was selected for fermentation of DORB. Despite the availability of the DORB in abundance at relatively lower prices, their inclusion in monogastric animal feeds is limited because of the presence of anti-nutritional factors. Anti-nutritional factors (ANFs) are concentrated in the bran fraction (Juliano, 1985) of rice bran. Most of the ANFs are protein in nature and thus heat labile, except for phytate. The phytate content of rice bran is high and varies from 20 to 70 g/kg of the bran; this may also have an effect on bioa- vailability of mineral (Warren & Farrell, 1991). The removal or reduction of these toxic anti-nutrients can be achieved by employing the micro-organism using SSF technology. The microbes growing during SSF may utilize and reduce the undesirable anti-nutrients. Solid-state fermentation is a very effective, economical viable technique to utilize the plant feed ingredient after reduction or removal of anti-nutrients and toxins (Sharath, Mohankumar, & Somashekar, 2014). Development of bioprocesses for biological detox- ification of agro-industrial residues has been the main focus of SSF research to eliminate or reduce phytic acid and trypsin inhibitor (Hassaan, Soltan, & Abdel-Moez, 2015). From the above discussion it is clear that SSF technology is very useful in improving the nutrient profile and helpful in bringing down the toxic anti-nutrients present in the agro-industrial residues. Therefore, the present research was conducted with an objective to study the effect of SSF on In vitro protein digestibility, fatty acid profile and anti-nutritional factor of DORB. https://doi.org/10.1016/j.foodres.2019.01.054 Received 8 April 2018; Received in revised form 16 January 2019; Accepted 21 January 2019 ⁎ Corresponding author. E-mail address: amitranjanfcri@gmail.com (A. Ranjan). Food Research International 119 (2019) 1–5 Available online 23 January 2019 0963-9969/ © 2019 Elsevier Ltd. All rights reserved. T