النشر العلمي

  • Physicochemical and Functional Properties of Flour and Protein Isolates Extracted from Seinat (Cucumis melo var. tibish) Seeds

 

he physicochemical and functional properties
of seinat seed flour (SSF), defatted seinat flour (DSSF),
and protein isolates were studied. Protein was extracted
from DSSF using an alkali solution with isoelectric
precipitation and freeze drying. Freeze dried seinat seed
protein isolates (FSSPI), SSF, and DSSF were evaluated
for their physicochemical and functional properties. SSF
contained high levels of crude fat and fiber (31.13% and
24.75%, respectively). FSSPI contained 91.83% protein
versus 28.58% for SSF. The amounts of potassium, the
mineral with the highest content, were 9,548.33, 6,439.03,
and 1,029 mg/100 g in SSF, DSSF, and FSSPI, respectively.
The functional properties were variable among samples.
The protein solubility of FSSPI was significantly higher
(p<0.05) than for DSSF and SSF. FSSPI has a significantly
better (p<0.05) foaming capacity, water/fat absorption
capacity, and bulk density than SSF and DSSF. FSSPI also
showed an emulsifying capacity comparable to commercial
soy protein isolates.
 

published in Food Sci. Biotechnol

  • hysicochemical properties and chemical composition of Seinat (Cucumis melo var. tibish) seed oil and its antioxidant activity

 

Seinat (Cucumis melo var. tibish) seeds were analyzed for their physiochemical properties and

chemical composition of the oil in addition to antioxidant activity. The crude oil content was 31.1%, while the

moisture, fiber, protein, ash and total sugar contents were 4.2%, 24.7%, 28.5%, 4.3%, and 6.9%, respectively.

The main fatty acids were linoleic, oleic, palmitic, and stearic acids (61.10%, 18.75%, 10.37% and 9.18%, respectively). The total phenolic content was 28.17 mg·g–1 oil. Seinat seed oil also contained a good level of tocopherols; of which δ-tocopherol (63.43%) showed the highest content. β-sitosterol was found at 289 mg·100g–1 oil of

total sterols (302 mg·100g–1) in the oil. The crude oil showed a good antioxidant activity in four assays including

reducing power, β-carotene bleaching inhibition activity, ABTS and DPPH radical scavenging activities.

 

published in GRASAS Y ACEITES

  • Separation and Structural Characterization of Tri-Glucosyl-Stevioside

Stevioside is a non-cariogenic and low-calorigenic diterpenoid glycoside has slightly bitterness and bad after taste.
Enzymatic modification by alternansucrase from Leuconostoc citreum SK24.002 was utilized in biotransformation
of stevioside to remove the bitter taste fully or partially and an aftertaste of the stevioside, using sucrose as donor
and stevioside as acceptor. Tri-glucosyl-stevioside produced during alternansucrase acceptor reaction of
stevioside were successfully separated using adsorption separation technology of macroporous adsorption resin
(AB-8) flowed by semipreparative high performance liquid chromatography. Structure of the product was
characterized to be 13-{[α-D-glucopyranosyl-(1→3)-α-D-glucopyranosyl-(1→6)-α-D-glucopyranosyl-(1→3)-β-Dglucopyranosyl-(
1→2)-β-D-glucopyranosyl]oxy}kaur-16-en-19-oic acid β-D glucopyranosyl ester on the basis of
extensive one dimension and two dimensional NMR and LC-ESI-MS in negative mode data.

published in Journal of Academia and Industrial Research (JAIR)

  • Stability of Stevioside and Glucosyl-Stevioside under Acidic Conditions and its Degradation Products

The stability of stevioside and mono- and di-glucosyl-stevioside(produced via Leuconostoccitreum
SK24.002 alternansucrase acceptor reaction), and the possible formation of the steviol at elevated temperature and
different pH levels was assessed, covering a typical pH range that simulated both relevant and extreme beverage
storage conditions. Acid solutions mixed with stevioside or mono- and di-glucosyl- stevioside after 24, 48, and 72 h
of storage time at 50 and 80°C were analysed. Under mild conditions (at a pH range of 2–6.5 over 72 h and 50°C)
stevioside and mono- and di-glucosyl-stevioside showed good stability. Degradation of up to 55% was observed at
pH 3 and 80°C after 72 h, and stevioside was less stable than mono-glucosyl-stevioside. Complete degradation was
observed at pH 2 and 80°C after 72 h. Stevioside and mono- and di-glucosyl-stevioside and their degradation
products were analysed by high-performance liquid chromatography with a diode array detector (DAD-HPLC) on
an NH2 analytical column, and the identity of the degradation products was confirmed by liquid chromatographyelectrospray
ionization mass spectrometry (LC-ESI-MS) in negative mode.

published in Journal of Food and Nutrition Research

  • Effect of shaking velocity on mono-glycosyl-stevioside productivityvia alternansucrase acceptor reaction

In this study, effect of shaking velocity on mono-glycosyl-stevioside production by Leuconostoc citreumSK24.002 alternansucrase acceptor reaction was investigated, with four different level of shaking velocity(75, 100, 125 and 150 rpm) up to 24 h at 25◦C, using sucrose as donor and stevioside as acceptor. Theresults revealed that mono-glycosyl-stevioside yield significantly increased with increase in the reactionshaking velocity and reached maximum yield of 3.78 ± .02 mg/mL at 150 rpm shaking velocity after 6 hof reaction. And an increase in the reaction shaking velocity up to 150 rpm reduced the final reactiontime and increased the productivity of mono-glycosyl-stevioside product such that the high quantityof mono-glycosyl-stevioside product was produced in only 6 h rather than 24 h. The mono-glycosyl-stevioside product was completely separated using macroporous resin AB-8 flowed by semi-preparativeHPLC. Macroporous resin AB-8 showed high selectivity and capacity toward mono-glycosyl-stevioside.The structure of mono-glycosyl-stevioside was characterized, as 13-{[-d-glucopyranosyl-(1→6)--d-glucopyranosyl-(1→2)--d-glucopyranosyl]oxy}kaur-16-en-19-oic acid -d-glucopyranosyl eater, acorroding to extensive 1D and 2D NMR (1H and 13C, COSY, HSQC, HMBC) and mass spectral data.

published in Journal of Molecular Catalysis B: Enzymatic

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