The Quality Assessment And Rapid Analytical Method Development Of Deep Fried Bread Sticks In Shanghai City

Fried bread sticks (FBS) is one of the most widely consumed deep fried foodproducts in China, is one of four diamond breakfast food in Shanghai.Because of its crisp, fragrant, crisp characteristics, loved by the people,especially the elderly and children. Its security is a growing concern as adeep-fried food of FBS. So it is necessary to investigate the safety of FBSfrom different vendors of Shanghai, choose nutritious and healthy meals tothe public to provide a scientific basis, and at the same time come up with anew approach to the determination of safety of FBS to provide rapid detectionmethod for the quality inspection departments to supervise the safety of FBSmore easily. Collect123pieces of FBS from different retailers (includingstreet vendors, chain stores, supermarket, canteen) of seven districts(including Pudong New Districts, Xuhui, Putuo, Zhabei, Yangpu, Jing an,and Changning)in shanghai to study. And this study is researched byfollowing aspects: 1. The fat and moisture content and rapid analytical method development ofFried Bread SticksLong-term to consume of high-calorie of FBS, easily lead to vasculardisease and coronary sclerosis, increase the incidence of obesity, diabetes,high cholesterol and cardiovascular disease. Chinese Nutrition Societyrecommend per person per day intake25g of cooking oil.The fat content ofFBS will be affected by the moisture content. Additionally both of the fat andmoisture content will affect the quality of the FBS.To determine the fatcontent of FBS using Soxhlet extraction method and determine the moisturecontent using drying method, and using an integrating sphere of Fouriertransform near-infrared spectroscopy (FT-NIR) and attenuated total thereflector (ATR) of Fourier transform mid-infrared spectroscopy（FT-IR) tocollect the infrared spectroscopy of FBS and combine to build a rapiddetermination of fat content of FBS stoichiometric model combined withpartial least squares (PLS) regression. The results show that there was greatdisparity in the fat content of FBS collected in Shanghai city, ranged from7.71%to30.89%, The mean and median of fat content (21.32%,21.53%) forFBS from street vendors were27.89%and35.75%higher than those collectedfrom the fast-food restaurants（16.67%,15.86%）. The moisture content forFBS ranged from17.39to31.87%.The mean and median of moisture content(26.44%,26.39%) for FBS from street vendors were11%higher than those collected from the fast-food restaurants(23.85%,23.82%). At the same timefound that the fat and moisture in FBS has certain negative correlation (R~2=0.452), the higher fat content, the lower moisture content in FBS.The resultsshow that the Fourier transform near-infrared spectroscopy technology can beused for rapid quantitative determination of fat and moisture content inFBS,the multiple correlation coefficient of predictive value and the actualvalue in PLS model is0.960and0.983; and Fourier transform infraredspectroscopy technology can be applied to the rapid screening of the fatcontent in FBS(R~2=0.883), moisture content predicted less effective(R~2=0.549).The results show that FT-NIR can be applied to rapid quantitativeanalysis of the fat and moisture content of FBS, and FT-IR only achieve rapidscreening of fat content of FBS,worse to predict moisture content.2. The polar components content and rapid analytical method development ofFried Bread SticksFry the FBS repeat at high temperature for a long time as easy to make therole of fats with oxygen, water and other, hydrolysis, oxidation andpolymerization, resulting the peroxide value, acid value, carbonyl value, Polarcomponents and other content exceeds the health standards of frying oil ofNational regulations in the frying oil, while producing a variety of harmfulsubstances.FBS will inhale of oil in the frying process. Detecting the polarcomponents content in oils to understand the frying oil quality of FBS. First extract oil from FBS, in accordance with international standards "polarcomponents (PC) in the animal and vegetable fats and oils Determination(ISO8420:2002(E)) using column chromatography method for thedetermination of PC content in fat of FBS. Collecting the infraredspectroscopy and NMR spectra of FBS using Fourier transform infraredspectroscopy (FT-NIR, FT-IR) and low-field NMR techniques.Using partialleast squares (PLS) regression to treat the infrared spectra, establish of astoichiometric model of the determination of PC content in FBS. The resultsshowed that both of the FT-NIR and FT-IR can rapid determination of the PCcontent in oils for FBS (FT-NIR: R~2=0.959, SEP=0.013, FT-IR: R~2=0.962,SEP=0.011), to achieve the purpose of assessment the frying oil quality.While use of the low-field NMR transverse relaxation time T21of the peakarea ratio occupied by the content of the component with the polarrelationship (R~2=0.846), can also achieve the purpose of rapid detection ofthe polar component content in oils for FBS.Measured simultaneously thepolar components content in oils for FBS is ranged from9.81to32.28%,exceeded the rate of13.13%(the state standards≤27%), the polarcomponents content in oils for FBS from chain stores are all qualified.3. The assessment of Aluminum content in FBSUse alum as a leavening agent to make the FBS, adding excessive will leadto excessive levels of aluminum. Excessive aluminum intake will lead to Alzheimer’s, rickets, iron deficiency anemia and other symptoms. In order tounderstand the situation of the aluminum content in Shanghai, for twoconsecutive years (2011-2012) collected a total of123pieces of FBS formdifferent chain stores, street vendors, supermarkets and canteens fritters inShanghai, using inductively coupled plasma atomic emission spectrometry todetermine the aluminum content in FBS.The analysis results show that thealuminum content in FBS from Shanghai ranged in4.15-1707.57mg/kg, theaverage value is660.36mg/kg, exceeded the rate of65.85%; including theaverage aluminum content from36chain stores is24.81mg/kg, allqualified;The average aluminum content in FBS from84street vendors is770.37mg/kg, exceeded the rate of95.24%; The average aluminum contentin FBS from two supermarket is29.76mg/kg, and all qualified; the aluminumcontent in FBS from a school canteen is721.94mg/kg, and unqualified. Thepublic can buy the FBS from chain stores and supermarkets, relevantdepartments should strengthen supervision of the the quality of FBS from thestreet vendors, to control the use of aluminum-containing leavening agent.