izpis_h1_title_alt

Neencimsko porjavenje pomarančnega soka
Lah, Monika (Author), Cigić, Blaž (Mentor) More about this mentor... This link opens in a new window

.pdfPDF - Presentation file, Download (1,33 MB)
MD5: 897528AD14C01F7B704C9F715ECB1481

Abstract
Pomarančni sok pomembno vpliva na dnevni vnos sadja, prehranske vlaknine in mikrohranil ter zmanjša verjetnost za pojav bolezni. Pomembna lastnost pomarančnega soka je njegova barva, zato je za živilsko industrijo porjavenje neželeno. Do porjavenja lahko v pogojih z nizko koncentracijo kisika prihaja zaradi Maillardove reakcije, pri kateri reagirajo proste amino skupine in reducirajoči sladkorji, in razgradnje askorbinske kisline. Posledica obeh reakcij je pojav rjavih pigmentov. Poleg spremembe barve lahko pride tudi do izgube hranil in kakovosti, ter tvorbe nekaterih neželenih spojin. V diplomski nalogi smo ugotavljali vpliv dodatkov askorbinske kisline, dehidroaskorbinske kisline, spermidina in putrescina na spremembo barve pomarančnega soka pri 50 oC. Predvidevali smo, da bodo vsi dodatki pospešili reakcije porjavenja. Barvo smo merili s kromametrom v trajanju dveh tednov in ugotovili, da le dehidroaskorbinska kislina pospešuje nezaželeno spremembo barve, saj se je v primerjavi s kontrolo značilno bolj povečala vrednost parametra a* in zmanjšala L*. Bioaktivna amina spermidin in putrescin ter askorbinska kislina, ki so naravno prisotni v pomarančnem soku, so v primerjavi s kontrolo delovali zaviralno na pojav porjavenja saj smo pri veliki večini časovnih točk določili manjše vrednosti a* in večje vrednosti L* v primerjavi s kontrolo.

Language:Slovenian
Keywords:pomarančni sok, neencimsko porjavenje, spermidin, putrescin, askorbinska kislina, dehidroaskorbinska kislina, Maillardova reakcija, barva
Work type:Bachelor thesis/paper (mb11)
Tipology:2.11 - Undergraduate Thesis
Organization:BF - Biotechnical Faculty
Year:2021
Publisher:[M. Lah]
Place:Ljubljana
UDC:663.81:634.31:577.1
COBISS.SI-ID:75507203 This link opens in a new window
Views:97
Downloads:35
Metadata:XML RDF-CHPDL DC-XML DC-RDF
 
Average score:(0 votes)
Your score:Voting is allowed only to logged in users.
:
Share:AddThis
AddThis uses cookies that require your consent. Edit consent...

Secondary language

Language:English
Title:Non-enzymatic browning of orange juice
Abstract:
Orange juice has an important role in daily fruit, dietary fiber and nutrients intake as well as in reducing chronical diseases. The attractive orange color is very important feature, therefore browning is unwanted in food industry. Browning can occur even in non-oxidizing medium, where the main browning reactions are Maillard reaction (a reaction between amino groups and reducing sugars) and degradation of ascorbic acid. Products of both reactions are brown pigments. Furthermore, the Maillard reaction and degradation of ascorbic acid can result in loss of nutrients, as well as in the formation of some unwanted compounds. In the thesis we studied the influence of ascorbic acid, dehydroascorbic acid, spermidine and putrescin on color change during incubation at 50 oC. We assumed that each of four compounds will stimulate the browning reaction. We used chroma meter to quantify the change in color during a period of two weeks. The results revealed that only dehydroascorbic acid potentiated unwanted change of color, as larger increase in the parameter a* and larger decrease in L* were found. Bioactive amines putrescine and spermidine and ascorbic acid that are naturally present in the orange juice, decreased the browning rate, as smaller a* and larger L* were determined in comparison with the control at most time points.

Keywords:orange juice, non-enzymatic browning, spermidine, putrescin, ascorbic acid, dehidroascorbic acid, Maillard reaction, color

Similar documents

Similar works from RUL:
Similar works from other Slovenian collections:

Comments

Leave comment

You have to log in to leave a comment.

Comments (0)
0 - 0 / 0
 
There are no comments!

Back