Protein detection

{{See also|Protein methods}}

Protein detection is used for clinical diagnosis, treatment and biological research.{{cite book |last1=Davis |first1=Jason J. |title=Engineering the Bioelectronic Interface: Applications to Analyte Biosensing and Protein Detection |date=2009 |publisher=Royal Society of Chemistry |isbn=978-0-85404-165-7 |oclc=701819884 }}{{pn|date=April 2025}} Protein detection evaluates the concentration and amount of different proteins in a particular specimen.{{cite book |doi=10.1002/9783527695188.ch6 |chapter=Protein Detection |title=Electrophoresis in Practice |date=2016 |pages=131–164 |isbn=978-3-527-33880-1 }} There are different methods and techniques to detect protein in different organisms. Protein detection has demonstrated important implications for clinical diagnosis, treatment and biological research.{{cite journal |last1=Zhang |first1=Hongquan |last2=Li |first2=Feng |last3=Dever |first3=Brittany |last4=Wang |first4=Chuan |last5=Li |first5=Xing-Fang |last6=Le |first6=X. Chris |title=Assembling DNA through Affinity Binding to Achieve Ultrasensitive Protein Detection |journal=Angewandte Chemie International Edition |date=4 October 2013 |volume=52 |issue=41 |pages=10698–10705 |doi=10.1002/anie.201210022 |pmid=24038633 }} Protein detection technique has been utilized to discover protein in different category food, such as soybean (bean), walnut (nut), and beef (meat).{{cite journal |last1=Liu |first1=Bin |last2=Teng |first2=Da |last3=Wang |first3=Xiumin |last4=Wang |first4=Jianhua |title=Detection of the Soybean Allergenic Protein Gly m Bd 28K by an Indirect Enzyme-Linked Immunosorbent Assay |journal=Journal of Agricultural and Food Chemistry |date=30 January 2013 |volume=61 |issue=4 |pages=822–828 |doi=10.1021/jf303076w |pmid=23317377 |bibcode=2013JAFC...61..822L }} Protein detection method for different type food vary on the basis of property of food for bean, nut and meat. Protein detection has different application in different field.

Protein detection in soybeans, walnuts, beef

= Purpose for protein detection in food =

File:Soybeans.jpg

Allergies from food have been noted to become common disease nowadays. The food allergies in the clinical demonstration present different signs, for example mild symptoms from itching in the mouth and swelling of the lips to critical anaphylactic response result in fatal consequences.{{cite journal |last1=Wang |first1=Xiaoyu |last2=Jiang |first2=Xiaofeng |last3=Zhu |first3=Shuxian |last4=Liu |first4=Lu |last5=Xia |first5=Junhan |last6=Li |first6=Lidong |title=Preparation of optical functional composite films and their application in protein detection |journal=Colloids and Surfaces A: Physicochemical and Engineering Aspects |date=December 2017 |volume=535 |pages=69–74 |doi=10.1016/j.colsurfa.2017.09.026 }} According to statistic, about 2% adults and 8% children are experiencing hypersensitivity from industrialized countries. In order to reduce potential threatening reactions for life, avoiding the consumption from these allergenic foods strictly is  the valid therapy. Therefore, sufficient description in term of potentially allergenic ingredients existing in food products is crucial and indispensable which can be monitored through protein detection.{{cite journal |last1=Cheng |first1=Lin |last2=Zhang |first2=Jie |last3=Lin |first3=Yan |last4=Wang |first4=Qiong |last5=Zhang |first5=XiuXiu |last6=Ding |first6=YanHua |last7=Cui |first7=Hanfeng |last8=Fan |first8=Hao |title=An electrochemical molecular recognition-based aptasensor for multiple protein detection |journal=Analytical Biochemistry |date=December 2015 |volume=491 |pages=31–36 |doi=10.1016/j.ab.2015.08.023 |pmid=26344894 }}{{cite journal |last1=Shimojo |first1=Naoshi |last2=Nakamura |first2=Masashi |last3=Sato |first3=Nayu |last4=Sano |first4=Akiyo |last5=Kobayashi |first5=Tsukane |last6=Yagami |first6=Akiko |last7=Kojima |first7=Atsushi |last8=Matsunaga |first8=Kayoko |title=Utility of Immunoproteomics in Soybean Allergy |journal=Journal of Allergy and Clinical Immunology |date=February 2016 |volume=137 |issue=2 |pages=AB139 |doi=10.1016/j.jaci.2015.12.587 |doi-access=free }}

= Rationale for protein detection in soybeans =

The soybean has been consumed in processed foods all over the word because of its high nutrient and easy processing characteristic such as soybean milk, tofu, meat alternatives, and brewed soybean products. microorganisms is used in brewage process for brewed soybean products like miso, soy sauce, natto and tempeh. Allergenicity stays in brewed soybean products. In Asian countries, these brewed soybean products are popular and traditional. The amount of patients from soybean allergy and the nearly infinite uses for soybean have gone up in the past a couple of years.{{cite journal |last1=Morishita |first1=Naoki |last2=Matsumoto |first2=Takashi |last3=Morimatsu |first3=Fumiki |last4=Toyoda |first4=Masatake |title=Detection of Soybean Proteins in Fermented Soybean Products by Using Heating Extraction |journal=Journal of Food Science |date=May 2014 |volume=79 |issue=5 |pages=T1049-54 |doi=10.1111/1750-3841.12461 |pmid=24811351 }}

== Previous method for protein detection in soybeans ==

During the last 30 years, broad methods and techniques were experimented to discover soybean protein. These methods and techniques can be conveyed to lab environment easily.{{Cite book|title=Protein blotting and detection : methods and protocols|date=2009|publisher=Humana Press|others=Kurien, Biji T., Scofield, R. Hal.|isbn=9781597455428|location=New York|oclc=371501294}} The original and traditional methods were designed and tested in molecular biology spectrum. Enzyme‐Linked Immunosorbent Assay technique containing high susceptibility and specificity is reliable method to investigate soybean proteins through applying a protein which can identify a foreign molecule. This has been evaluated as a vacuolar protein including a molecular block of 34 kDa. The ELISA illustrated sufficient repeatability and reproducibility in lab assessment. But it can not test protein in soybean existing in brewed soybean products.{{Cite journal|last1=Morales-Narváez|first1=Eden|last2=Guix|first2=Maria|last3=Medina-Sánchez|first3=Mariana|last4=Mayorga-Martinez|first4=Carmen C.|last5=Merkoçi|first5=Arben|date=2014|title=Micromotor Enhanced Microarray Technology for Protein Detection|journal=Small|language=en|volume=10|issue=13|pages=2542–2548|doi=10.1002/smll.201303068|pmid=24634101|hdl=10261/126975|hdl-access=free}} There are different studies to conduct experiments to assess soybean protein through ELISA. However, reproducibility, cross-reactivity and low repeatability make measurement difficult to be reliable in processed foods. These methods can not discover soybean protein staying in brewed soybean products.{{cite book |doi=10.1007/978-1-4939-2718-0 |title=Detection of Blotted Proteins |series=Methods in Molecular Biology |date=2015 |volume=1314 |isbn=978-1-4939-2717-3 }}{{pn|date=April 2025}}

== Current method for protein detection in soybeans ==

Compared with previous method, a heating process is involved in current abstraction technique to investigate soybean protein existing in brewed products. Since the heating process can deactivate the microbial proteolytic enzymes, the current abstraction technique can be used to disclose soybean protein in brewed soybean products.{{cite journal |last1=Lin |first1=Chenxiang |last2=Katilius |first2=Evaldas |last3=Liu |first3=Yan |last4=Zhang |first4=Junping |last5=Yan |first5=Hao |title=Self-Assembled Signaling Aptamer DNA Arrays for Protein Detection |journal=Angewandte Chemie International Edition |date=11 August 2006 |volume=45 |issue=32 |pages=5296–5301 |doi=10.1002/anie.200600438 |pmid=16847867 }} The heating abstraction technique can be demonstrated as the following. To produce the good dispersibility for the specimen in the extraction buffer to carry out the heating process, 19mL of abstraction buffer is mixed with five glass beads in five millimeter diameter and 1 g of food homogenate. At 5, 15 and 60 min variable time, the mixture is abstracted under 25, 40, 60, 80 and 100 ° variable temperature through the heating in a water bath followed by every 5 minutes vortexing. Food abstractions generated through the previous and the current technique are centrifuged for 20 minutes at three thousand gram, then the supernatant is filtered off by a filter paper. The filtrate is gathered and applied for analysis immediately acting as the food specimen abstract.{{cite journal |last1=Park |first1=Do Hyun |last2=Lee |first2=Jae-Seung |title=Functionalized nanoparticle probes for protein detection |journal=Electronic Materials Letters |date=May 2015 |volume=11 |issue=3 |pages=336–345 |doi=10.1007/s13391-014-4383-0 |bibcode=2015EML....11..336P }} The calibration standard solutions needs to be prepared to disclose soybean proteins by using ELISA.  A three hundred milligram soybean powder specimen is mixed with a twenty milliliter compound including 0.5 M NaCl, 0.5% SDS, 20 mM Tris-HCl (pH 7.5), and 2% 2-ME. The compound is then shaken at room temperature for 16 hours for abstraction. The abstract is centrifuged for 30 minutes at twenty thousand gram, then the supernatant is selected by a 0.8-μm microfilter paper. The protein substance from the initial abstract is inspected with a 2-D Quant Kit. The initial abstract is diluted to 50 ng/mL combined with 0.1% SDS, 0.1% 2-ME, 0.1 M PBS (pH 7.4), 0.1% BSA, and 0.1% Tween 20, and it is deposited for ELISA at 4 °C playing as the calibration standard solution.

== Conclusion for current protein detection method in soybeans. ==

The detection limit for the ELISA is 1 μg/g and it can not assess soybean proteins existing in brewed soybean products due to degradation of the proteins in soybean through microbial proteolytic enzymes staying in the brewed products. The microbial proteolytic enzymes possibly restrain the detection of soybean protein storing in the brewed soybean products. The current abstraction technique can control protein degradation through the microbial proteolytic enzymes. The microbial proteolytic enzymes can be inhibited by heating, pH, and protease inhibitors in general.{{cite journal |last1=Nong |first1=Rachel Yuan |last2=Gu |first2=Jijuan |last3=Darmanis |first3=Spyros |last4=Kamali-Moghaddam |first4=Masood |last5=Landegren |first5=Ulf |title=DNA-assisted protein detection technologies |journal=Expert Review of Proteomics |date=February 2012 |volume=9 |issue=1 |pages=21–32 |doi=10.1586/epr.11.78 |pmid=22292821 }} The variable heating temperatures and abstraction times are examined to decide the ideal heating temperature and time to control microbial proteolytic enzymes. The heating conditions showed to optimize the control of microbial proteolytic enzymes is 80 °C for 15 minutes. So the heating temperature for the abstraction is set to 80 °C and the time is set to 15 minutes for the current abstraction technique.{{cite book |doi=10.1002/9783527626687 |title=Detection of Highly Dangerous Pathogens |date=2009 |isbn=978-3-527-32275-6 |editor-last1=Kostic |editor-last2=Butaye |editor-last3=Schrenzel |editor-first1=Tanja |editor-first2=Patrick |editor-first3=Jacques }}{{pn|date=April 2025}}

The current abstraction technique can restrain the degradation of soybean proteins through microbial proteolytic enzymes and can detect soybean protein in most brewed soybean products. The current abstraction technique combined with the heating is a useful and sensitive tool to discover soybean protein stored in processed foods and brewed soybean products. Without impacting microbial proteolytic enzymes, this method is appropriate to quantify soybean protein in processed foods. The proposed extraction and ELISA technique can be applied to control labeling systems for soybean ingredient through a trusty manner.

File:Black Walnut nut and leave detail.JPG

File:Juglans regia 2009 G2.jpg

=Rationale for protein detection in walnuts=

English walnuts (Juglans regia) and black walnuts (Juglans nigra) are two main types of walnuts in the market across the world. Walnuts are utilized as a valuable ingredient due to favorable health attributes, sensory properties and consumer sensation.{{Cite journal|last1=Ros|first1=E|last2=Nunez|first2=I|last3=Perez-Heras|first3=A|date=2004|title=A walnut diet improves endothelial function in hypercholesterolemic subjects. A randomized crossover trial|journal=ACC Current Journal Review|language=en|volume=13|issue=6|pages=19–20|doi=10.1016/j.accreview.2004.06.062}}{{cite journal |last1=Almoosawi |first1=Suzana |last2=Fyfe |first2=Lorna |last3=Ho |first3=Clement |last4=Al-Dujaili |first4=Emad |title=The effect of polyphenol-rich dark chocolate on fasting capillary whole blood glucose, total cholesterol, blood pressure and glucocorticoids in healthy overweight and obese subjects |journal=British Journal of Nutrition |date=28 March 2010 |volume=103 |issue=6 |pages=842–850 |doi=10.1017/S0007114509992431 |pmid=19825207 |oclc=706594347 |doi-access=free }} Shelled walnuts are broadly applied as ingredients in different foods such as salad, ice creams, bread and meat alternative. Walnut oil is introduced as a good source of mono- and polyunsaturated fatty acids and tocopherols.{{cite journal |last1=Savage |first1=G. P. |last2=Dutta |first2=P. C. |last3=McNeil |first3=D. L. |title=Fatty acid and tocopherol contents and oxidative stability of walnut oils |journal=Journal of the American Oil Chemists' Society |date=September 1999 |volume=76 |issue=9 |pages=1059–1063 |doi=10.1007/s11746-999-0204-2 }} And it is adopted as a food ingredient in salad dressings particularly. Walnut hull extract is considered as a dietary supplement and a seasoning in the food industry. In addition, ground walnut shells can be used in industrial field as extenders, carriers, fillers and abrasives for example jet cleaners. Tree nuts are regarded as one of the most common allergenic foods around the world.{{cite book |title=Preparation and use of food-based dietary guidelines |date=1998 |publisher=World Health Organization |isbn=978-92-4-120880-2 |hdl=10665/42051 |hdl-access=free |oclc=40216171 }}{{pn|date=April 2025}}  Allergic reactions from tree nuts can be fierce and life threatening.{{cite journal |last1=Silver |first1=M. |last2=Comline |first2=R. S. |title=Transfer of gases and metabolites in the equine placenta: a comparison with other species |journal=Journal of Reproduction and Fertility. Supplement |date=October 1975 |issue=23 |pages=589–594 |pmid=1529 }}{{cite journal |last1=Teuber |first1=Suzanne S. |last2=Comstock |first2=Sarah S. |last3=Sathe |first3=Shridhar K. |last4=Roux |first4=Kenneth H. |title=Tree nut allergy |journal=Current Allergy and Asthma Reports |date=January 2003 |volume=3 |issue=1 |pages=54–61 |doi=10.1007/s11882-003-0013-x |pmid=12542995 }} Individuals with walnut allergies can have result in fatal and near-fatal reactions from the unintended ingestion of walnuts, other tree nuts or possibly contamination of food with the walnuts ingredient.{{syn|date=April 2025}}{{Cite book|title=Asthma '84: Pharmacologic Update : October 31 to November 3, 1984, Rancho Mirage, California|last=Asthma '84: Pharmacologic Update (1984 : Rancho Mirage, Calif.)|date=1985|publisher=Mosby|oclc=12425311}}{{title?|which title is being cited from the conference}}{{Cite journal|last1=Bock|first1=S.Allan|last2=Muñoz-Furlong|first2=Anne|last3=Sampson|first3=Hugh A.|date=2001|title=Fatalities due to anaphylactic reactions to foods|journal=Journal of Allergy and Clinical Immunology|language=en|volume=107|issue=1|pages=191–193|doi=10.1067/mai.2001.112031|pmid=11150011|doi-access=free}}{{cite journal |last1=Merritt |first1=William M. |last2=Lin |first2=Yvonne G. |last3=Han |first3=Liz Y. |last4=Kamat |first4=Aparna A. |last5=Spannuth |first5=Whitney A. |last6=Schmandt |first6=Rosemarie |last7=Urbauer |first7=Diana |last8=Pennacchio |first8=Len A. |last9=Cheng |first9=Jan-Fang |last10=Nick |first10=Alpa M. |last11=Deavers |first11=Michael T. |last12=Mourad-Zeidan |first12=Alexandra |last13=Wang |first13=Hua |last14=Mueller |first14=Peter |last15=Lenburg |first15=Marc E. |last16=Gray |first16=Joe W. |last17=Mok |first17=Samuel |last18=Birrer |first18=Michael J. |last19=Lopez-Berestein |first19=Gabriel |last20=Coleman |first20=Robert L. |last21=Bar-Eli |first21=Menashe |last22=Sood |first22=Anil K. |title=Dicer, Drosha, and Outcomes in Patients with Ovarian Cancer |journal=New England Journal of Medicine |date=18 December 2008 |volume=359 |issue=25 |pages=2641–2650 |doi=10.1056/NEJMoa0803785 |pmid=19092150 |pmc=2710981 }}{{cite journal |last1=Sampson |first1=Hugh A. |last2=Mendelson |first2=Louis |last3=Rosen |first3=James P. |title=Fatal and Near-Fatal Anaphylactic Reactions to Food in Children and Adolescents |journal=New England Journal of Medicine |date=6 August 1992 |volume=327 |issue=6 |pages=380–384 |doi=10.1056/NEJM199208063270603 |pmid=1294076 |doi-access=free }}{{cite journal |last1=Baker |first1=Dewleen G. |last2=Mendenhall |first2=Charles L. |last3=Simbartl |first3=Loretta A. |last4=Magan |first4=Laura K. |last5=Steinberg |first5=Jonathan L. |title=Relationship Between Posttraumatic Stress Disorder and Self-Reported Physical Symptoms in Persian Gulf War Veterans |journal=Archives of Internal Medicine |date=13 October 1997 |volume=157 |issue=18 |pages=2076–2078 |doi=10.1001/archinte.1997.00440390062009 |pmid=9382663 |oclc=772409021 }}{{cite journal |last1=Kemp |first1=Stephen F. |last2=Lockey |first2=Richard F. |last3=Wolf |first3=Bruce L. |last4=Lieberman |first4=Phil |title=Anaphylaxis: A Review of 266 Cases |journal=Archives of Internal Medicine |date=11 September 1995 |volume=155 |issue=16 |pages=1749–1754 |doi=10.1001/archinte.1995.00430160077008 |pmid=7654108 }}{{cite journal |last1=Warner |first1=J.O. |title=How dangerous is food allergy in childhood? |journal=Pediatric Allergy and Immunology |date=June 2002 |volume=13 |issue=3 |pages=149–150 |doi=10.1034/j.1399-3038.2002.00059.x |pmid=12144634 }}{{cite journal |last1=Oki |first1=Toshikazu |last2=Yoshimoto |first2=Akihiro |last3=Sato |first3=Seiji |last4=Takamatsu |first4=Akira |title=Purine nucleotide pyrophosphotransferase from Streptomyces morookaensis, capable of synthesizing pppApp and pppGpp |journal=Biochimica et Biophysica Acta (BBA) - Enzymology |date=December 1975 |volume=410 |issue=2 |pages=262–272 |doi=10.1016/0005-2744(75)90228-4 |pmid=1088 }}{{cite journal |last1=Boyd |first1=George K. |title=Fatal Nut Anaphylaxis in a 16-Year-Old Male: Case Report |journal=Allergy and Asthma Proceedings |date=July 1989 |volume=10 |issue=4 |pages=255–257 |doi=10.2500/108854189778959966 |pmid=2792751 }} To prevent walnut allergic reactions, the only effective way is to avoid walnuts in the diet.{{cite journal |last1=Taylor |first1=Stephen L. |last2=Bush |first2=Robert K. |last3=Busse |first3=William W. |title=Avoidance Diets—How Selective Should We Be? |journal=Allergy and Asthma Proceedings |date=November 1986 |volume=7 |issue=6 |pages=527–532 |doi=10.2500/108854186779045502 }} The appropriate labeling of processed foods with walnuts ingredient is critical to protect walnut-allergic consumers. There are a couple of circumstances cause undeclared walnut residues such as sharing equipment between walnut-containing and other formulations and undeclared walnuts in ingredients.{{cite journal |last1=Dawson |first1=R. M. |title=The Reaction of Choline and 3,3-Dimethyl-1-Butanol with the Acetylenzyme from Acetylcholinesterase |journal=Journal of Neurochemistry |date=December 1975 |volume=25 |issue=6 |pages=783–787 |doi=10.1111/j.1471-4159.1975.tb04408.x |pmid=1471 }} The enzyme-linked immunosorbent assay (ELISA) can be used as the technique to detect walnuts residues with great sensitivity and specificity since walnuts allergic Individuals can have allergic reactions with low (milligram) amounts of walnuts.{{cite journal |last1=Prado |first1=M. |last2=Ortea |first2=I. |last3=Vial |first3=S. |last4=Rivas |first4=J. |last5=Calo-Mata |first5=P. |last6=Barros-Velázquez |first6=J. |title=Advanced DNA- and Protein-based Methods for the Detection and Investigation of Food Allergens |journal=Critical Reviews in Food Science and Nutrition |date=17 November 2016 |volume=56 |issue=15 |pages=2511–2542 |doi=10.1080/10408398.2013.873767 |pmid=25848852 }} Several different techniques can be applied to discover walnut residues as well such as polymerase chain reaction (PCR) method and ELISA method on the basis of polyclonal antisera raised against a particular 2S albumin walnut protein.{{cite journal |last1=Brežná |first1=B. |last2=Hudecová |first2=L. |last3=Kuchta |first3=T. |title=A novel real-time polymerase chain reaction (PCR) method for the detection of walnuts in food |journal=European Food Research and Technology |date=July 2006 |volume=223 |issue=3 |pages=373–377 |doi=10.1007/s00217-005-0214-8 }}{{cite journal |last1=Yano |first1=Takeo |last2=Sakai |first2=Yumiko |last3=Uchida |first3=Kohji |last4=Nakao |first4=Yoshiki |last5=Ishihata |first5=Kimie |last6=Nakano |first6=Shigeru |last7=Yamada |first7=Toshihiro |last8=Sakai |first8=Shinobu |last9=Urisu |first9=Atsuo |last10=Akiyama |first10=Hiroshi |last11=Maitani |first11=Tamio |title=Detection of Walnut Residues in Processed Foods by Polymerase Chain Reaction |journal=Bioscience, Biotechnology, and Biochemistry |date=23 July 2007 |volume=71 |issue=7 |pages=1793–1796 |doi=10.1271/bbb.70118 |pmid=17617706 |doi-access=free }}

== Current method for protein detection in walnuts ==

The sandwich-type walnut ELISA is the current method used to detect protein in walnuts. The sandwich-type walnut ELISA can be applied as a critical analytical technique by food manufacturers and regulatory agencies for hygiene validation and the assessment of allergen control strategies.{{fact|date=April 2025}}

===Immunogen preparation===

A mixture of several brands of English walnuts are used to produce the immunogen. The mixed walnuts need to be washed by deionized distilled water 6 times and air-dried. Portion of the walnuts are dry-roasted for 10 minutes at 270 ◦F. The roasted or raw walnuts are cleaved, frozen, and ground to a refined particle size through the blender. The ground roasted and ground raw walnuts are defatted and filtered. Then, the powdered raw or roasted walnuts are air-dried thoroughly. Both the defatted, powdered raw, and roasted walnuts can be utilized as immunogens. Protein concentrations of the defatted powdered immunogens are set through the Kjeldahl method with 46.4% raw defatted walnut and 34.9% roasted defatted walnut.{{cite journal |last1=Doi |first1=Hirotoshi |last2=Touhata |first2=Yuki |last3=Shibata |first3=Haruki |last4=Sakai |first4=Shinobu |last5=Urisu |first5=Atsuo |last6=Akiyama |first6=Hiroshi |last7=Teshima |first7=Reiko |title=Reliable Enzyme-Linked Immunosorbent Assay for the Determination of Walnut Proteins in Processed Foods |journal=Journal of Agricultural and Food Chemistry |date=10 September 2008 |volume=56 |issue=17 |pages=7625–7630 |doi=10.1021/jf801550h |pmid=18681443 |bibcode=2008JAFC...56.7625D }}

===Polyclonal antibody production and titer determination===

Polyclonal antibodies are generated in 1 sheep, 1 goat, and 3 New Zealand white rabbits with each immunogen. The initial subcutaneous injections are given to the 10 animals including 3 rabbits, 1 sheep, and 1 goat on multiple sites with the defatted powdered immunogen and Freunds Complete Adjuvant. Titer values of collected antisera are evaluated by a noncompetitive ELISA method with walnut protein from abstracts of the proper raw or roasted immunogen.

===Cross-reactivity study and ELISA method===

A variety of tree nuts, seeds, legumes, fruits and food ingredients are assessed for cross-reactivity in the walnut ELISA assay. The modified sandwich ELISA can be used to detect walnuts residues with sheep antiroasted walnut and rabbit antiroasted walnut antisera used as the capture and detector antibodies respectively.

==Conclusion for current protein detection method in walnuts==

Walnut residues can be disclosed at 1 ppm quantitation limit in a diversity of food such as ice cream, muffins, cookies and chocolate. The walnut ELISA can be conducted to detect possible walnut residues allergy in other foods from sharing equipment and to evaluate the sanitation procedures targeted on removal of walnut residues from shared equipment in the food industry.

File:Mafate cattle dsc00749.jpg

= Rationale for protein detection in beef =

It has been reported that animal feedingstuffs containing processed animal protein (PAP) contaminated with prions have caused BSE infection of the cattle. Processed animal proteins (PAP) has been prohibited to apply as feed material for all farmed animals except fish meal currently. In addition, infections from consumption of undercooked raw beef has been declaimed to be an important pathogen for Enterohemorrhagic Escherichia coli O157:H7.{{cite journal |last1=Savoye |first1=F. |last2=Feng |first2=P. |last3=Rozand |first3=C. |last4=Bouvier |first4=M. |last5=Gleizal |first5=A. |last6=Thevenot |first6=D. |title=Comparative Evaluation of a Phage Protein Ligand Assay with Real-Time PCR and a Reference Method for the Detection of Escherichia coli O157:H7 in Raw Ground Beef and Trimmings |journal=Journal of Food Protection |date=January 2011 |volume=74 |issue=1 |pages=6–12 |doi=10.4315/0362-028X.JFP-10-271 |pmid=21219756 |doi-access=free }}

== Method for protein detection in beef ==

For processed animal protein, the specific polymerase chain reaction (PCR) based procedure parallelled with microscopic method is utilized to detect processed animal protein (PAP) in feedingstuffs. The limit detection for PCR has been evaluated on 0.05% for beef, 0.1% for pork and 0.2% for poultry meat and bone meal. Microscopic method can disclose 66.13% doubtful samples of feedingstuffs. Combined the results from the use of the microscopic and PCR methods, it has been stated that the molecular biology methods can be executed as a supplementary method for PAP detection.{{cite journal |last1=Kunze |first1=H |last2=Bohn |first2=E |last3=Bahrke |first3=G |title=Effects of psychotropic drugs on prostaglandin biosynthesis in vitro |journal=Journal of Pharmacy and Pharmacology |date=November 1975 |volume=27 |issue=11 |pages=880–881 |doi=10.1111/j.2042-7158.1975.tb10239.x |pmid=1505 }}

For undercooked raw beef, in order to make sure a safe beef supply, sensitive and quick detection techniques for E. coli O157:H7 are important in the meat industry. Three different techniques can be used in raw ground beef: the VIDAS ultraperformance E. coli test (ECPT UP), a noncommercial real-time (RT) PCR method and the U.S. Department of Agriculture, Food Safety and Inspection Service (USDA-FSIS) reference method to detect E. coli O157:H7. 25 g of individual raw beef samples and 375 g of raw beef composites can be examined for optimal enrichment times and the efficacy of testing. 6 hours of enrichment is sufficient for both the VIDAS ECPT UP and RT-PCR methods for 25 g samples of each type of raw ground beef, but 24 hours of enrichment is acquired for 375 g samples, Both the VIDAS ECPT UP and RT-PCR methods can generate similar results with those gained from the USDA-FSIS reference method after 18 to 24 hours of enrichment. Low levels of E. coli O157:H7 in 25 g of various types of raw ground beef can be disclosed through these methods, E. coli O157:H7 in composite raw ground beef up to 375 g can be detected as well.

= Implication from protein detection =

{{further|Protein microarray}}

Protein detection in cells from the human rectal mucous membrane can imply colorectal disease such as colon tumours, inflammatory bowel disease.{{cite journal |last1=Anderson |first1=Neil |last2=Suliman |first2=Ibnauf |last3=Bandaletova |first3=Tatiana |last4=Obichere |first4=Austin |last5=Lywood |first5=Rupert |last6=Loktionov |first6=Alexandre |title=Protein biomarkers in exfoliated cells collected from the human rectal mucosa: implications for colorectal disease detection and monitoring |journal=International Journal of Colorectal Disease |date=October 2011 |volume=26 |issue=10 |pages=1287–1297 |doi=10.1007/s00384-011-1263-z |pmid=21698353 }} Protein detection based on antibody microarrays can implicate life signature for example organics and biochemical compounds in the Solar System in astrobiology field.{{cite journal |last1=Parro |first1=Víctor |last2=Rivas |first2=Luis A. |last3=Gómez-Elvira |first3=Javier |title=Protein Microarrays-Based Strategies for Life Detection in Astrobiology |journal=Space Science Reviews |date=March 2008 |volume=135 |issue=1–4 |pages=293–311 |doi=10.1007/s11214-007-9276-1 |bibcode=2008SSRv..135..293P }} Protein detection can monitor soybean protein labeling system in processed foods to protect consumers in a reliable way. The labeling for soybean protein declaimed by protein detection has indicated to be the most important solution. Detailed labeling description for the soybean ingredients in refined foods is required to protect the consumer.

References

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