| Tomato(Lycopersicon esculentum Mill)is a kind of fruit also vegetable with rich nutritional values,which is widely cultivated and consumed all over the world.More than 90%of water content in tomato makes it hard to be stored,so in addition to fresh food,a lot of tomatoes were used for processing into tomato ketchup and tomato juice drinks.However,due to high fiber content in the tomato seed and peel,tomato juice drinks were prone to stratified sedimentation and instability.Therefore,it is usually necessary to filter out the peel residues in the production process,which will produce a large number of by-products,causing resource waste and environmental pollution.Dynamic high pressure microfluidization(DHPM)used as a new homogenization equipment could effectively improve the physical stability of food suspension system.However,the traditional dynamic high pressure microfluidization was only used in lab-scale research and application on soft food systems containing less fiber due to its narrow cavity,limited particle size of the feed and low handling capacity.In this paper,an Industry-scale Microfluidizer System(ISMS)developed based on the principle of DHPM technology was used to prepare whole tomato beverage without removing peel residues,and the effects of ISMS pressure on the physical stability,nutritional quality and bioaccessibility of lycopene of whole tomato beverage were studied.And whole tomato beverage was further produced by formula optimization.The main findings are as follows:1.The whole tomato beverage was prepared by ISMS under different pressures(0,30,60,90 and 120 MPa)using tomatoes with a material-to-water ratio of 1:2(w/w).Laser diffraction particle size analysis results showed that ISMS significantly reduced the particle size of whole tomato beverage,and D[4,3]significantly decreased with increasing pressure,from 151.00?m treated at 0 MPa to 30.20?m after 120 MPa treatment.The PSD of samples changed from bimodal to three peaks,and the PSD became narrower.It was observed by optical microscope the cell clusters became smaller and the cell structure was destroyed into cell fragments to varying degrees after ISMS treatment,and the cell contents were released.The results of rheological properties showed that the apparent viscosity,consistency coefficient and viscoelasticity of the whole tomato beverage system were slightly decreased and the fluidity was increased under ISMS treatment.Zeta potential analysis showed that ISMS treatment had no significant effect on the electrostatic stability of the whole tomato beverage,and the value was stable between-(24.47-25.50)m V.After ISMS treatment,whole tomato beverage formed network with stronger water-holding capacity,and the precipitate weight ratio was nearly doubled(from 15.83%to 29.63%).And samples treated with ISMS(30-120 MPa)did not show any stratified deposition in stationary conditions for 28 days.After ISMS 120 MPa treatment,the interface sedimentation speed decreased by 21%,and the turbidity decreased significantly with the increasing treatment pressure.The influence of different pressure ISMS treatments on the physical stability of whole tomato beverage followed an asymptotic behavior.The change under high pressure was less than that under low pressure,and the big change mainly occurred between 0 and 30 MPa,while the change under 30 to 120 MPa was small.It can be concluded from above results that ISMS could reduce the particle size by destroying the tissue and cell structure of whole tomato beverage,and promote the formation of a stronger network to reduce particle sedimentation and pulp separation,hence improving physical stability.2.The effects of different pressure treatments of ISMS on the quality and nutritional composition of whole tomato beverage were investigated.The results showed there was no significant change in p H value after ISMS treatment,the total range was between 4.34 and 4.38,and there was no significant difference in the content of total soluble solids.The results of the spectrophotometer showed that the brightness,redness and yellowness of the whole tomato beverage were increased slightly,and the color became more saturated.The total phenol content and antioxidant activity of the whole tomato beverage reached the highest value after ISMS 90 MPa treatment,and the total phenol content reached 10.04±0.45mg gallic acid(GAE)/100m L.The ISMS made the carotenoids more dispersed,and the total carotenoid and lycopene levels increased when the treatment pressure was higher than 90 MPa.After ISMS treatment,the bioaccessibility of lycopene increased significantly from the initial value of 9.03%to 11.26%(increased by 24.70%)at 90 MPa and 14.08%(increased by 55.92%)at 120MPa.The effect of ISMS on the main nutrients and the bioaccessibility of lycopene in whole tomato beverage changed under the condition of high pressure treatment(?90MPa),which was different from its effect on physical stability.3.Based on the above research results,the whole tomato beverage prepared by ISMS 90 MPa was selected to optimize the formulation of stabilizers and thickeners,color protection agents,and sweet-sour taste.The results showed that only adding 0.1%(w/w)of pectin could make it stable for 9 months.Vitamin C(Vc)had better color protection effect than Vitamin E(V_E)within the allowable addition range of national standard.When the addition amount of Vc was 0.08%(w/w),it had good color protection effect,which could make the retention rate of a*reach to 96%.According to the sensory evaluation,the white granulated sugar with the added mass fraction of10%had the best sweet-sour taste.The conclusions of this study could provide a theoretical basis for ISMS to improve the utilization rate of tomato resources and its application on whole component fruit and vegetable juice products. |
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