scholarly journals Shelf-Life Stability of Ready-to-Use Green Rooibos Iced Tea Powder—Assessment of Physical, Chemical, and Sensory Properties

Molecules ◽  
2021 ◽  
Vol 26 (17) ◽  
pp. 5260
Author(s):  
Chantelle Human ◽  
Dalene de Beer ◽  
Magdalena Muller ◽  
Marieta van der Rijst ◽  
Marique Aucamp ◽  
...  

Green rooibos extract (GRE), shown to improve hyperglycemia and HDL/LDL blood cholesterol, has potential as a nutraceutical beverage ingredient. The main bioactive compound of the extract is aspalathin, a C-glucosyl dihydrochalcone. The study aimed to determine the effect of common iced tea ingredients (citric acid, ascorbic acid, and xylitol) on the stability of GRE, microencapsulated with inulin for production of a powdered beverage. The stability of the powder mixtures stored in semi-permeable (5 months) and impermeable (12 months) single-serve packaging at 30 °C and 40 °C/65% relative humidity was assessed. More pronounced clumping and darkening of the powders, in combination with higher first order reaction rate constants for dihydrochalcone degradation, indicated the negative effect of higher storage temperature and an increase in moisture content when stored in the semi-permeable packaging. These changes were further increased by the addition of crystalline ingredients, especially citric acid monohydrate. The sensory profile of the powders (reconstituted to beverage strength iced tea solutions) changed with storage from a predominant green-vegetal aroma to a fruity-sweet aroma, especially when stored at 40 °C/65% RH in the semi-permeable packaging. The change in the sensory profile of the powder mixtures could be attributed to a decrease in volatile compounds such as 2-hexenal, (Z)-2-heptenal, (E)-2-octenal, (E)-2-nonenal, (E,Z)-2,6-nonadienal and (E)-2-decenal associated with “green-like” aromas, rather than an increase in fruity and sweet aroma-impact compounds. Green rooibos extract powders would require storage at temperatures ≤ 30 °C and protection against moisture uptake to be chemically and physically shelf-stable and maintain their sensory profiles.

Foods ◽  
2021 ◽  
Vol 10 (7) ◽  
pp. 1657
Author(s):  
Karolina Östbring ◽  
María Matos ◽  
Ali Marefati ◽  
Cecilia Ahlström ◽  
Gemma Gutiérrez

Rapeseed press cake (RPC), the by-product of rapeseed oil production, contains proteins with emulsifying properties, which can be used in food applications. Proteins from industrially produced RPC were extracted at pH 10.5 and precipitated at pH 3 (RPP3) and 6.5 (RPP6.5). Emulsions were formulated at three different pHs (pH 3, 4.5, and 6) with soy lecithin as control, and were stored for six months at either 4 °C or 30 °C. Zeta potential and droplet size distribution were analyzed prior to incubation, and emulsion stability was assessed over time by a Turbiscan instrument. Soy lecithin had significantly larger zeta potential (−49 mV to 66 mV) than rapeseed protein (−19 mV to 20 mV). Rapeseed protein stabilized emulsions with smaller droplets at pH close to neutral, whereas soy lecithin was more efficient at lower pHs. Emulsions stabilized by rapeseed protein had higher stability during storage compared to emulsions prepared by soy lecithin. Precipitation pH during the protein extraction process had a strong impact on the emulsion stability. RPP3 stabilized emulsions with higher stability in pHs close to neutral, whereas the opposite was found for RPP6.5, which stabilized more stable emulsions in acidic conditions. Rapeseed proteins recovered from cold-pressed RPC could be a suitable natural emulsifier and precipitation pH can be used to monitor the stability in emulsions with different pHs.


Author(s):  
А.Л. Майтаков ◽  
Л.Н. Берязева ◽  
Н.Т. Ветрова ◽  
К.Б. Плотников

Разработан новый быстрорастворимый продукт (кисель) с определенным фазовым составом и строением на основе молочной сыворотки и местного растительного сырья – черноплодной рябины (Aronia melanocarpa). Разработана модель технологии производства быстрорастворимого гранулированного продукта (кисель) на основе молочной сыворотки и черноплодной рябины. Исследована сохраняемость киселя в трех температурных режимах: 1-й (21 ± 1)°С; 2-й с низкой плюсовой температурой (5 ± 1)°С; 3-й с повышенной (39 ± 1)°С при влажности окружающей среды 80%. По окончании годичного исследования сохраняемости при температурных режимах (21 ± 1)°С и (5 ± 1)°С изменений в органолептических показателях продукта не наблюдали. Скорость растворения продукта при температурных условиях хранения (21 ± 1)°С и (5 ± 1)°С не изменялась на протяжении 9 мес. Установлено, что при хранении в условиях пониженных положительных температур 4–6°С и в режиме комнатной температуры (21 ± 1)°С исследуемый пищеконцентрат по окончании 6 мес. хранения не изменил свойств по показателям качества. Сроки испытания продукта превышали по длительности в 2 раза заданный срок хранения (коэффициент запаса). Результаты испытаний явились основанием для разработки технической документации на производство быстрорастворимых гранулированных плодово-ягодных киселей. A new fast – soluble product (kissel) with a certain phase composition and structure based on whey and local plant raw materials Aronia melanocarpa. A model of technology for the production of a rapidly soluble granular product (kissel) based on whey and Aronia melanocarpa has been developed. The stability of kissel in three temperature modes was studied: 1st (21 ± 1)°C; 2nd with a low plus temperature (5 ± 1)°C; the 3rd with the increased (39 ± 1)°C at 80% ambient humidity. At the end of a year-long study at temperature conditions (21 ± 1)°С and (5 ± 1)°С, no changes in the organoleptic characteristics of the product were observed. Dissolution rate of the product under storage temperature conditions (21 ± 1)°C and (5 ± 1)°C did not change for 9 months. It is established that when stored at low positive temperatures 4–6°C. With and at room temperature (21 ± 1)°C. At the end of 6 months of storage, the food concentrate under study did not change its properties in terms of quality. The product testing period was 2 times longer than the specified storage period. The test results were the basis for the development of technical documentation for the production of instant granulated fruit and berry kissel.


2012 ◽  
Vol 32 (1) ◽  
pp. 9-14 ◽  
Author(s):  
Tatiane Regina Albarici ◽  
José Dalton Cruz Pessoa

This study assesses the storage temperature effect on the anthocyanins of pasteurized and unpasteurized açaí pulp. The data was obtained using a pasteurized and lyophilized pulp (PLP) to evaluate the temperature effect (0, 25, and 40 °C). Part of non-pasteurized frozen pulp (NPP) was pasteurized (NPP-P) at 90 °C for 30 seconds; both pulps were stored at 40 °C. The anthocyanin content reduction in the drink was evaluated from the half-life time (t1/2), activation energy (Ea), temperature quotient (Q10), and the reaction rate constant (k). The t1/2 of the PLP anthocyanins stored at 40 °C was 1.8 times less than that stored at 25 °C and 15 times less than that stored at 0 °C; therefore, the higher temperatures decreased the stability of anthocyanins. The pasteurization increased the t1/2 by 6.6 times (10.14 hours for NPP and 67.28 hours for NPP-P). The anthocyanin degradation on NPP-P followed a first order kinetic, while NPP followed a second order kinetic; thus it can be said that the pasteurization process can improve the preservation of anthocyanins in the pulp.


1970 ◽  
Vol 44 (2) ◽  
pp. 147-156
Author(s):  
Tamanna Sultana ◽  
GP Savage ◽  
NG Porter ◽  
DL McNeil ◽  
JR Sedcole

Isothiocyanates (ITCs) contained in purees extracted from wasabi (Wasabia japonica (Miq) Matsum) can be used to manufacture a range of interesting spicy foods. In New Zealand, local manufacturers are showing interest in producing various forms of processed wasabi based sauces. However, isothiocyanates have been shown to degrade quickly in some situations. Therefore, in this study, the stability of allyl ITC was investigated in three wasabi flavoured products stored at four different temperatures (4, 10, 20 and 30°C) for 22 weeks. Two creamy (mayonnaise and tartare) sauces and a non-creamy sauce were prepared from an original recipe and flavoured with a known volume of "wasabi oil". Two types of pouches (clear and metallic plastic) were used to store each product and allyl ITC content was measured in the stored sauces at two week intervals. The initial level of allyl ITC found in mayonnaise, tartare and smoky tomato sauces were 415.3, 411.4 and 144.7 mg/ kg respectively, prior to storage. Temperature showed a strong influence in reducing allyl ITC (P=0.005 to <0.001) but no significant effect was identified for the two types of packets used. The non-creamy smoky tomato sauce was very unstable at 10°C or higher temperatures and the allyl ITC contents reduced rapidly with increasing storage temperatures. For instance, at 30°C, a 66% loss occurred by week 2 and a 90% loss occurred by week 6 in the smoky tomato sauce. However, mayonnaise and tartare sauces had a shelf life of 8 to 9 weeks with only a marginal reduction in allyl ITC (2% overall) at all the stored temperatures (4-30°C). These creamy sauces were characterized by a sudden fall in 10 weeks ending in a 69-70% loss of allyl ITC at 22 weeks. No microbial growth occurred in any of the sauces stored at any of the temperatures during the course of this storage experiment though very small change of colour was noticed for the sauces when stored at 30°C. Keywords: Bangladesh J. Sci. Ind. Res. 44(2), 147-156, 2009DOI: 10.3329/bjsir.v44i2.3665Bangladesh J. Sci. Ind. Res. 44(2), 147-156, 2009


2005 ◽  
Vol 68 (10) ◽  
pp. 2085-2094 ◽  
Author(s):  
MARIA J. GRANDE ◽  
ROSARIO LUCAS ◽  
EVA VALDIVIA ◽  
HIKMATE ABRIOUEL ◽  
MERCEDES MAQUEDA ◽  
...  

Enterocin AS-48 is a candidate bacteriocin for food biopreservation. Before addressing application of AS-48 to vegetable-based foods, the interaction between AS-48 and vegetable food components and the stability of AS-48 were studied. Enterocin AS-48 had variable interactions with fruit and vegetable juices, with complete, partial, or negligible loss of activity. For some juices, loss of activity was ameliorated by increasing the bacteriocin concentration, diluting the juice, or applying a heat pretreatment. In juices obtained from cabbage, cauliflower, lettuce, green beans, celery, and avocado, AS-48 was very stable for the first 24 to 48 h of storage under refrigeration, and decay of activity was markedly influenced by storage temperature. In fresh-made fruit juices (orange, apple, grapefruit, pear, pineapple, and kiwi) and juice mixtures, AS-48 was very stable for at least 15 days at 4°C, and bacteriocin activity was still detectable after 30 days of storage. Gradual and variable loss of activity occurred in juices stored at 15 and 28°C; inactivation was faster at higher temperatures. In commercial fruit juices (orange, apple, peach, and pineapple) stored at 4°C, the bacteriocin was completely stable for up to 120 days, and over 60% of initial activity was still present in juices stored at 15°C for the same period. Commercial fruit juices stored at 28°C for 120 days retained between 31.5% (apple) and 67.71% (peach) of their initial bacteriocin activity. Solutions of AS-48 in sterile distilled water were stable (120 days at 4 to 28°C). Limited loss of activity was observed after mixing AS-48 with some food-grade dyes and thickening agents. Enterocin AS-48 added to lettuce juice incubated at 15°C reduced viable counts of Listeria monocytogenes CECT 4032 and Bacillus cereus LWL1 to below detection limits and markedly reduced viable counts of Staphylococcus aureus CECT 976.


2013 ◽  
Vol 295-298 ◽  
pp. 150-154
Author(s):  
Feng Jie Wang ◽  
Xin Qiao Dong ◽  
Xiao Liu

Development natural pigment retained a variety of nutrition composition is extremely research value.Water Wax Trees Fruit was as raw materials,citric acid aqueous solution was as extracting agent.Amaranthine pigment extraction method were studied on fully grasping the stability of the natural amaranthine pigment and no damage to the water wax fruit biological activity.The effect of extraction yield were studied on Water Wax Trees Fruit natural amaranthine pigment.The results show that the better extraction conditions are extraction temperature at 70 °C, extraction time for 3h,citric acid concentration1.0 % , the material/liquid ration(g/ml) 1:5.The extraction yield is 2.95%.Ultraviolet absorption maximum wavelength is 280 nm.


2021 ◽  
Vol 26 (4) ◽  
pp. 34-39
Author(s):  
ATTILA BAKSA ◽  
DAVID GONCZI ◽  
LASZLA PETER KISS ◽  
PETER ZOLTAN KOVACS ◽  
ZSOLT LUKACS

The stability of thin-walled cylindrical shells under axial pressure is investigated. The results of both experiments and numerical simulations are presented. An appropriate finite element model is introduced that accounts not only for geometric imperfections but also for non-linearities. It is found that small geometrical imperfections within a given tolerance range have considerable negative effect on the buckling load compared to perfect geometry. Various post buckling shell shapes are possible, which depend on these imperfections. The experiments and simulations show a very good correlation.


2016 ◽  
Vol 47 (4) ◽  
Author(s):  
Jebur & et al.

This study was aimed to know the efficiency of partially purified L- asparaginase produced from local isolate from Erwinia spp. to reduce the percentage of acrylamide formed in Biscuit. Four types of biscuit from wheat flour were prepared (T1, T2, T3, T4),and T1 as control. High performance liquid chromatography technique was used to estimate acrylamide ratio in biscuit , Effect of enzyme addition  on flour chemical and rheological properties was studied, also dough behavior ,gluten percentage, water absorption and amylase enzyme activity was estimated. The results revealed  that  the  addition of  experimental asparaginase ( specific activity 20.5 unite mg-1 ) with 1% of flour weight lead to reduce in acrylamide formation in Biscuit  to 89 %  compared  to  control sample ( in absence of enzyme ) . Moreover, the addition of Asparagine to flour at 0.1 % of its weight, where L- asparaginase was available caused a negative effect on enzyme efficiency in reducing the acrylamide in biscuit. So the level of acrylamide was reduced to 57.7 %. In the other hand , the percentage of acryl amide in biscuit was increased to   233 % when the asparagine was added to mixture in absence of L- asparaginase .Addition of  the enzyme to flour have no effect on the percentage value of gluten but improved the  stability of dough .The  enzyme  addition also led to increase amylases activities.  Addition of experimental enzyme had no effect on quality and sensory evaluation of biscuit.


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