Impact Of Pulsed Electric Field And Ultrasound On The Quality Of Almond Milk

Almonds seeds have got more consideration due to their high nutritional composition and health interests.Almonds seeds are a good source of essential fatty acids,protein,dietary fibers,and micronutrients such as magnesium,potassium,arginine,tocopherols,and calcium.Almond nuts also contain phytonutrients such as phenolics acids,carotenoids,polyphenols,phytosterols,lignin,and sphingolipids.Due to a load of these nutrients consumption of almond nuts has also been associated with a reduction of gallstones formation,cancer risks,heart disease,and several helpful metabolic consequences.As a nutritional point of view,almond nuts are valuable food and useful constituent for different food products as they comprise a variety of phytochemicals,micro-and macronutrients.Almond milk is known with different names like plant-based beverages,non-dairy beverage,vegetable milk,and nut milk because it is an aqueous extract of almond seeds.Almond milk is a dairy milk substitute for lactose intolerance and cholesterol conscious consumers Plants-based drinks are a popular choice for different kinds of consumers such as vegetarians and vegans.Plant-based beverages such as almond milk graduated from just rehydration and refreshment beverages to functional beverages due to their nutritional composition and possible health benefits.Food processing and extraction of valuable compounds mainly rely on traditional approaches that have been linked with high-temperature inputs.Conventional processing practices have been used successfully to increase food safety and shelf life of food products.Conventional processing practices have been used successfully to increase food safety and shelf life of food products,while the high thermal inputs through these methods induce unfavorable variations in the nutritional quality of food products.Due to this concern,Novel non-thermal processing techniques such as pulsed electric field(PEF)and ultrasound(US)techniques have been acquired much attention in the food processing and preservation industries in recent years.These processing technologies are considered to be efficient non-thermal techniques that may overwhelm the difficulties correlated with conventional methods such as nutritional losses and deleterious variations in sensory characteristics.The basic objective of this research was to ascertain the ability of US and PEF for the extraction of bioactive compounds and processing of almond milk with its impact on different bioactive compounds,physicochemical properties,antioxidant activities,rheological,structural properties,colloidal stability,physical stability,enzymatic and microbial inactivation.In the first part of this research,investigate the combined impact of the pulsed electric field(PEF)and ultrasound(US)to evaluate the physicochemical,bioactive compounds and chemical structure of almond extract.Almond extract was first treated with PEF and then with the US Combined treatment(PEF-US)has attained the highest value of total phenolic,total flavonoids,condensed tannins,anthocyanin contents and antioxidant activity in DPPH,reducing power and metal chelating activity than all other treatments.Among all those treatments,there was a slightly visible difference in the color.Moreover,FT-IR spectra indicate that the effect of PEF-US on almond extract did not produce new carbonyl compounds,but led to the higher concentration of these compounds.In the second part,the effects of the pulsed electric field(PEF)on the rheological,structural and physicochemical properties of almond milk were evaluated.Results indicated that there was a significant increase in electrical conductivity,cloud value,and cloud stability,while a significant decrease was observed in viscosity and non-enzymatic browning after PEF treatments.The particle size was significantly reduced and monodisperse distributions were observed,particle size reduction further confirmed by Scanning Electron Microscopy.Whiteness Index,clarity and physical stability of samples were improved,without affecting either protein stability or viscosity The rheological behavior of all samples was described using a Herschel-Bulky model.PEF treatments decreased the apparent viscosity and changed the consistency index(K).The denaturation temperatures and apparent enthalpy of almond milk samples were modified by PEF treatments.In the third part,examine the impact of thermal treatment(TT)and pulsed electric field(PEF)on the overall quality of almond milk.Results showed an increase in free amino acids and volatile compounds production with increasing the electric field(EF)strengths,while the fatty acids profile did not change significantly as compared to the untreated sample.The storage study showed a reduction in bioactive compounds and antioxidant activities with periods.It was observed that bioactive antioxidant compounds were higher in PEF treated almond milk at 28 kVcm-1 than untreated and thermal treated samples.PEF processing improved the product microbial shelf-life during storage and enhanced with increasing of EF strength or by applying the TT.Lipoxygenase and peroxidase of the PEF treated sample at 28 kV/cm were inactivated by 50%and 45%,respectively;whereas TT achieved 59%and 68%.The color variation was observed on PEF and TT but PEF has less impact on product color as compared to TT.The colloidal stability was significantly increased as a result of particle size and sedimentation index reduction after PEF treatment.However;the processing treatments did not significantly change the pH,soluble solids,and acidity values.This project proposed that the combined treatment of PEF and US could be useful for the extraction of bioactive compounds as well as improving the stability of volatile compounds.This study also indicated that the PEF treatment can be an excellent alternative to thermal processing to assure high nutritional values,microbiological stability,rheological,structural properties,fresh-like qualities and shelf life of almond milk.The results of this research proposed that PEF can enhance the quality of almond beverage and may be employed for the processing at an industrial scale.