Study On The Preparation And Characterization Of Fish Bone Powder And The Nutritional,functional And In Vitro Digestiblity Characteristics Of Flavored Snacks

Global fisheries production has increased tremendously in the past few decades due to the high use of fish meat in growing population of the world that is increasing day by day.This production is generating a huge amount of waste(20 MT)as a by-products or discards.These discards or by-products from aquatic processing have remained a big challenge for waste management and their efficient use for human food.As such,scientists and academics are trying to develop new methods which tend to reduce this waste and utilizing it for human food.The aquatic waste is of great interest due to its characteristics such as high nutrition,easy to obtain and low cost.Among the aquatic waste,fish bone(the most abundant percentage of solid waste from fisheries processing)has gained considerable attention due to wide availability,low cost and fulfilling the Halal and Kosher requirements compared with bones from mammalian and vertebrate sources.Fish bone is comprised of organic(collagen and gelatin)and inorganic portion(calcium,phosphorous,sodium,irons and other minerals)with high biological value.The concept of fish bone as a human food has led to the utilization of fish bone-based products which are promising source of high quality nutrition and a substitute of other expensive ingredients used for the fortification purpose.There is an increasing demand for the fish meat and fish bone based products in the recent years due to good nutritional value and improved functional properties of food especially snack foods.For many decades,the snack industry remained dependent on the wheat flour and other starches due to the attributes such as low cost,ease of availability and starch-protein interaction especially the role of gluten protein.However,these ingredients can create some problems to human health(allergens to gluten protein)as well as some downfalls regarding physio-chemical properties such as poor water holding capacity,extensive viscoelastic behavior upon heating and low biological value.Additionally,the intensive load on wheat flour has induced the urge to find the alternative to gluten protein and wheat starch which would be more heather and having improved functional characteristics.Therefore,there is growing interest to replace the gluten protein in snacks and add those ingredients that are of high nutrition and improved physio-chemical properties.Thus,during this research,fish bone powder was prepared and fortified in fish meat based fried snacks.Additionally,the replacement of wheat flour with cassava starch in fish bone based snacks was investigated.At the end,the effect of different emulsifiers was studied in order to prepare fish meat based fried snacks.Herein,this thesis carried out the following research contents and related results which are as follow:1.Fish bone powder(FBP)from grass carp(Ctenopharyngodon idella)was prepared and characterized using different processing methods and analytical techniques.The results showed that,compared with other methods,the ?-potential of fish bone powder prepared with pressure heat treatment(PHT)with milling was significantly(p<0.05)increased(15.2 mV)and facilitated size reduction(5.2 ?m)while only the heat treatment improved the proximate composition.The collagen denaturation was followed using Fourier transform infrared spectroscopy(FTIR)at 1338 cm-1 peak while the amide regions(?,? and ?),carbonate(870 cm-1)and phosphate(565 and 1030 cm-1)groups were identified in all treatments.The scanning electron microscopy showed the variation in particle size and porous structure of FBP.Moreover,the calcium and protein in vitro digestibility was significantly high in the PHT groups along with high essential amino acids at intestinal stage.The results propose the feasibility of using PHT as an alternative to the thermal treatment to prepare FBP.These findings provided the useful information and evidences revealed that FBP can be used for human food.2.In this study,previously prepared fish bone dispersion(F.B)was fortified in snacks based on wheat flour(W.F)with fish meat(F.M)and potato powder(P.P)addition A formulation blend of W.F 10-50 g,potato powder(P.P)0-40 g,F.M 0-30 g,and F.B 0-20 g was used to investigate different responses using response surface methodology(RSM).The results revealed that F.M had significant influence on protein content and inverse relation with water holding capacity(WHC)and hardness.Whereas,F.B increased hardness,ash and calcium contents but decreased WHC,expansion,and color parameters.Furthermore,scanning electron microscopy(SEM)confirmed the effect of different variables on product morphology.The results of amino acids revealed that fish meat and fish bone significantly increased the essential amino acids as compared to control.Optimized formulation(w/w)was W.F 35.71%,P.P 28.57%,F.M 21.42%and F.B 14.28%with 37%bioavailable calcium,improved texture,and nutritional value.3.Wheat flour(W.F)was replaced with cassava starch(CS)at 5 different levels of 10,20,30,40 and 50%(w/w)to prepare fried snacks.The hardness and lightness were increased significantly(p<0.05)due to CS addition.The protein,moisture,fat content,WHC and expansion considerably(p<0.05)decreased by CS addition.Fourier transform infrared(FTIR)spectroscopy revealed that secondary structure of amides I ?-helix(1650-1660 cm-1)along with amide ? region(1540 cm-1)was changed when CS was added.Moreover,starch-protein complex was identified by X-ray diffraction(XRD)analysis while no starch-protein-lipids matrix was observed.It was evident by scanning electron microscopy(SEM)images that starch-protein matrix was interrupted in 40%or high percentage of CS.Furthermore,in vitro Ca bioavailability was also decreased significantly.The results suggest the feasibility of adding 40%CS as an alternative to wheat flour in fried snacks.4.The effect of ionic and non-ionic emulsifiers at 3 different levels of 0.15,0.30 and 0.45%/100 g of flour on physio-chemical properties,microstructure and water distribution of fish-meat based fried snacks was examined.The findings showed that addition of distilled mono-glycerides(DMG)decreased the strength of starch-protein network which resulted in increased expansion and decreased WHC.The addition of diacetyl tartaric acid esters of mono-glycerides(DATEM)increased the WHC while oil uptake was decreased.Pasting properties such as breakdown,peak viscosity,and pasting temperatures were increased with the addition of DATEM compared with DMG and control.Scanning electron microscopy(SEM)analysis showed that DATEM strengthen the starch-protein matrix with less voids while DMG increased the intercellular spaces between the molecules of starch and protein.Low field nuclear magnetic resonance(LF-NMR)relaxometery analysis revealed that amount of free water(T21)was decreased and bound water(T23)was increased in DATEM samples compared to control and DMG.Moreover,the protein in vitro digestibility did not change significantly in DMG group and control.The findings suggested that 0.30%DATEM can be used in snacks with better physio-chemical properties and functional properties.