Cream Formation Research Articles

Spontaneously Assembled Nano-aggregates in Clear Green Tea Infusions from Camellia ptilophylla and Camellia sinensis.

Tea nano-aggregates spontaneously assembled in clear tea infusions are considered as the precursors of tea cream, although their molecular basis remains obscure. Here, we characterized nano-aggregates in green tea infusions from Camellia ptilophylla, a peculiar tea variety with 6.0% of theobromine, and Camellia sinensis as the control for comparative purpose. Numerous negatively charged spherical colloidal particles of 50-100 nm in diameter were primarily found in both green tea infusions. Catechins, proteins, and carbohydrates were confirmed as the dominant components in green tea nano-aggregates. In addition, iron, copper, nickel, proteins, and gallated catechins exhibited higher aggregating affinity than other components, whereas methylxanthines and calcium contributed to the transformation of nano-aggregates into tea cream. Green tea nano-aggregates were partly destroyed by simulated gastrointestinal digestion, and removing theses peculiar particles dramatically attenuated the bioaccessibility of methylxanthines, theanine, and some catechin monomers in green tea infusions. This study enhanced our knowledge of molecular interactions in the formation of green tea cream and provided insight into physicochemical profiles, phytochemical nature, and functional effects of green tea nano-aggregates.

Physical Characteristics, Chemical Composition, Organoleptic Test And The Number Of Microbes In The Biscuits With Addition Of Flour Banana Peels

The purpose of this study to analyze the physical characteristics, chemical composition and organoleptic test of biscuit flour with the addition of flour banana peel. Materials used are banana peels Kepok. Kepok banana peel has been found to contain high fiber food. Biscuit-making stage includes the formation of cream, adding flour and wheat flour dietary fiber from banana peels to concentrations of 0% as control, 25%, 50% and 75% of 100 grams of wheat flour; mixing; molding; baking in the oven for 20-25 minutes with a temperature of 180°C. Parameters to be measured, namely the physical characteristics include: hardness, softness, consistency, crispness. Furthermore, the biscuits were tested by chemical analysis (proximate). Organoleptic test include: aroma, taste, mouthfeel, aftertaste. Data were analyzed statistically using SAS computing programs. Physical and organoleptic test results biscuits with the addition of flour banana peels has sufficient level of preference between like-liked. Based on the results of the proximate analysis of biscuits with the addition of flour banana peels has generally been in accordance with the National Standards of Indonesia (SNI). Conclusion of the study that the addition of flour banana peels in biscuits has the potential to become functional foods that contain high fiber.

Application of the Natural Refrigerant Mixture R-290/DME to a Soft Ice Cream Refrigerator

Due to the ozone depletion issue, R-502, which had long been used as the refrigerant of an ice cream refrigerator, has been replaced by R-404A. However, global warming potential (GWP) of R-404A is high, and thus, a replacement refrigerant is necessary in the long term. Natural refrigerants, such as R-290 or DME (dimethylether), could be a choice. In this study, an ice cream refrigerator cycle was optimized using R-290/DME mixture (mass fraction 65/35). The optimization was accomplished through a search for the proper refrigerant charge amount and the opening of the expansion valve. For the present ice cream refrigerator having 2.8[Formula: see text]L freezer volume, the optimum charge amount was 900[Formula: see text]g, and the optimum valve opening was [Formula: see text]120[Formula: see text]. At this configuration, the ice cream formation time was 3[Formula: see text] 6[Formula: see text] and COP was 2.0. The ice cream formation time was much shorter than when R-404A was used, and the COP was increased by more than 100%. For actual usage of the refrigerant, however, the flammability issue of the R-290/DME mixture should be cleared.

Purification of polyphenols from green tea leaves by ultrasound assisted ultrafiltration process

Abstract Application of ultrafiltration membranes is a promising alternative to recovery target components from natural substrates, but some drawbacks should be considered such as the membrane fouling. Here we propose the application of the ultrasound assisted ultrafiltration process for the purification of phenolic compounds from green tea extract. Comparison between the processes with and without ultrasound showed that the state steady flux through the membrane of 5 kDa was 4 times greater in the ultrasound assisted process than in the process without ultrasound. This flux improvement is associated with the decrease in cake formation and in the total resistance (from 17.8 to 10.2 × 1013 m−1). The flux decay profiles were better described by pore blockage models than by the cake formation model, since the cake was formed in the first minutes of filtration and, after that, the particles of relative small size entered in the membrane pores. Moreover, the ultrasound facilitated the permeation of phenolic compounds through the membrane. Comparison between ultrafiltration membranes of different MWCO suggests that the membrane of 20 kDa presented high purity of catechin components in the permeate (49% of EGCG related to the total polyphenol content). Turbidity values of ultrafiltration permeates remained lower than 5 NTU after 30 days of storage under refrigeration and any tea cream formation was observed, which suggests great permeate stability. Thus, the ultrasound assisted ultrafiltration process with the membrane of 20 kDa is suggested for the purification of phenolic compounds from green tea extract in order to ensure great permeate flux, purity of phenolic compounds and extract stability.

Moisture impact on extractability of phospholipids from leftover egg yolk after enzymatic treatment using supercritical carbon dioxide

The leftover egg yolk after immunoglobulin Y (IgY) extraction was subjected to enzymatic hydrolysis with Protease P and Lipase AY30, which resulted in the formation of cream. The extractability and purity of phosphatidylcholine (PC) and total phospholipids (PL) at three levels of moisture content in cream (freeze dried cream, 20% and 45%, w/w) were studied using supercritical carbon dioxide (SC-CO2) extraction with ethanol addition (8%, mole%) as co-solvent at 48.3MPa and 70°C. The results were compared to those obtained from fresh yolk and dry yolk. The highest recoveries of PC and total PL were for freeze-dried cream and cream with 20% moisture in which the recovery of PC was about 85% and 65%, respectively, based on the initial mass of yolk used for cream formation and 94% and 106% recovery, respectively, based on the amount of cream used as extraction feed. The highest purity of PC was about 87% obtained from fresh yolk and 84% from cream with 20% moisture content. This study showed that enzymatic treatment of the pellet can improve the recovery of PC and PL from egg yolk at moisture contents of up to 20%.

Black tea cream effect on polyphenols optimization using statistical analysis

Black tea cream formation is an inhibitor for the polyphenols separation since it decreases the amount of available polyphenols. Four factors that are considered to have an impact in the amount of tea cream and polyphenols availability are studied: temperature, amount of solids, pH and amount of EDTA.By using a design of experiments instead of a one-factor-at-a-time, additional information such as interaction effects can be obtained. The objective is to determine the optimum combination range for the factors that minimize the cream formation, while maximizing the amount of polyphenols in the clear phase.Statistical analysis is used to determine which factors significantly influence the responses and to generate polynomial models. This is a very effective tool and it indicates that EDTA is the only non-relevant factor. The optimization results in a 37% increase in the yield of theaflavins and a 20% increase in the yield of catechins.

Membrane Clarification of Tea Extracts

The ready-to-drink (RTD) tea beverages are becoming increasingly popular owing to the health benefits associated with tea polyphenols, but instability due to development of haze and formation of tea cream is a common problem encountered in the product. Membrane technology provides a scope to produce natural, additive-free RTD teas while overcoming the major disadvantages associated with the conventional decreaming methods. Approaches employing membranes for the clarification of extracts from black and green tea have been discussed together with their relative advantages and limitations. The article also outlines the concerns to be addressed in the future attempts employing membrane technology.

Use of Urgotul SSD® to reduce bacteria and promote healing in chronic wounds

This product focus seeks to give an overview of the management of wound bioburden in relation to the use of antimicrobial dressings, according to recent guidelines and best practice statements. Identification of critical colonisation/localised infection and the role of biofilms is a key aspect of effective wound management. Silver antimicrobial dressings are efficient in reducing bacteria in wounds, but must be used appropriately to prevent overuse. Silver sulphadiazine has traditionally been used for the treatment of burns or Pseudomonas infection in leg ulceration, often in a cream formation. This article will be looking specifically at the effective use of Urgotul SSD in three critically colonised/non healing wounds.

The impact of Ca2+ combination with organic acids on green tea infusions

The effect of Ca2+ in brewing water on the organic acid content, turbidity, and formation of tea cream and sediment in green tea infusions was studied. When the Ca2+ concentration of the brewing water was >40mgL−1, the green tea infusion became more turbid. The turbidity of the tea infusion was highly negatively correlated with the contents of oxalic acid (R=−0.89, p<0.01), quinic acid (R=−0.90, p<0.01) and tartaric acid (R=−0.82, p<0.01). Oxalic acid on its own interacted with Ca2+ at low concentrations, whereas polyphenols and protein did not. In conclusion, Ca2+ in brewing water influences the quality of a tea infusion by inducing tea cream and sediment formation from combination of Ca2+ and organic acids, such as oxalic acid, quinic acid and tartaric acid. Ca2+ and oxalate are the main metal ion and anion, respectively, involved in tea cream and sediment formation on tea infusion cooling or concentrating.

Application of Enzymes in the Production of RTD Black Tea Beverages: A Review

Ready-to-drink (RTD) tea is a popular beverage in many countries. Instability due to development of haze and formation of tea cream is the common problem faced in the production of RTD black tea beverages. Thus decreaming is an important step in the process to meet the cold stability requirements of the product. Enzymatic decreaming approaches overcome some of the disadvantages associated with other conventional decreaming methods such as cold water extraction, chill decreaming, chemical stabilization, and chemical solubilization. Enzyme treatments have been attempted at three stages of black tea processing, namely, enzymatic treatment to green tea and conversion to black tea, enzymatic treatment to black tea followed by extraction, and enzymatic clarification of extract. Tannase is the most commonly employed enzyme (tannin acyl hydrolase EC 3.1.1.20) aiming at improving cold water extractability/solubility and decreasing tea cream formation as well as improving the clarity. The major enzymatic methods proposed for processing black tea having a direct or indirect bearing on RTD tea production, have been discussed along with their relative advantages and limitations.

Tea Creaming in Nonfermented Teas from Camellia sinensis and Ilex vomitoria

Tea creaming is the development of a cloudy or hazy appearance in tea and ready-to-drink tea products on cooling and is highly undesirable in the tea beverage industry. Commonly associated with fermented black or oolong teas, the objective of this study was to investigate the physicochemical mechanism of the formation of tea cream in nonfermented green tea (Camellia sinensis) and a caffeine-containing botanical tea from yaupon holly (Ilex vomitoria) that is free of catechin-based polyphenolics. Four tea-creaming activators (phenolics, soluble protein, caffeine, and metal ions) were added to tea infusions as well as decaffeinated teas created by chloroform extraction. Tea-creaming activators increased the weight and turbidity of both teas with the exception of soluble protein addition (as bovine serum albumin) to green tea, whereas the greatest increase in turbidity occurred with the addition of metal ions in green tea. Tea creaming was equally developed at three incubation temperatures (4, 25, and 40 °C) in both teas, but tea-creaming compositions in each tea were different at the incubating temperatures. The antioxidant capacity of each tea was lowered after creaming due to the loss of antioxidants that participated in tea cream formation.

ENZYMATIC TREATMENT OF BLACK TEA (CTC AND KANGRA ORTHODOX) USINGPENICILLIUM CHARLESIITANNASE TO IMPROVE THE QUALITY OF TEA

ABSTRACT Tannase mediated biotransformation of black tea (CTC and Kangra orthodox) was investigated. Black tea infusion treated with tannase showed that both epigallocatechin (EGC) gallate and epicatechin (EC) gallate of tea catechins were hydrolyzed by this enzyme into EGC and EC, respectively, accompanied by 11.2-fold (CTC tea) and 10.29-fold (Kangra orthodox tea) increase in gallic acid concentration. The tannase treated tea infusion showed reduction in tea cream formation and an increase in antioxidant activity to 1.73- and 1.61-fold, respectively. However, there was no change in the content and concentration of volatile compounds. Moreover, the results also showed that there was an improvement in the quality of tannase treated black tea infusion in relation to color, brightness, strength and flavor as compared with control. PRACTICAL APPLICATION The tannase mediated biotransformation of tea infusion (CTC and Kangra orthodox) improves the quality of tea in relation to reduction in tea cream formation. The reduction will help to produce a turbidity free, cold water soluble instant tea or tea extract. Furthermore, on tannase treatment, an increase in an antioxidant activity was also observed due to certain flavonoids present in tea that show potential health benefits against cardiovascular diseases and cancer. There was no significant change in the volatile compounds that thereby resulted in an improved color, brightness, strength and flavor of tea.

Effects of Chemical Components on the Amount of Green Tea Cream

The relationship between the amount of tea cream and the chemical components contents in the original green tea infusion was investigated. The results showed that the amounts of tea cream in the green tea infusions obtained from different cultivars and different parts of new shoots were varied. There were many chemical components participating in the formation of green tea cream. However, there were only the contents of caffeine ( Y=0.85, P<0.01) and polyphenols ( Y=0.65, P<0.05) in the original green tea infusion highly correlated with the amount of green tea cream. Stepwise regression analysis of overall chemical components indicated that the contents of caffeine and gallated catechins in the original green tea infusion had a significant effect ( P<0.01) on green tea cream levels. Cream (g L −1)=−172.071+0.129× C caffeine+0.024× G gallated catechins ( R 2=0.936). The amount of green tea cream can be predicted by the contents of gallated catechins and caffeine in the original tea infusion. Principal component analysis also indicated that catechins, minerals, and polysaccharides were the important chemical components in the formation of green tea cream.

Analysis of cream formation in green tea concentrates with different solid concentrations

The formation of tea cream in the green tea concentrates of different solid concentrations (5, 10, 20, 30, 40, 50 and 60°Brix) was investigated. The results showed a good positive correlation (γ = 0.98, p ≤ 0.05) between the amount of tea cream and the solid concentrations from 5 to 40°Brix, while the amount of tea cream in the tea concentrates of 50 and 60°Brix decreased acutely. Total sugar, caffeine and catechins were found to be the main chemical components of tea cream in the green tea concentrate. The large decrease of the amount of tea cream in the tea concentrates of 50 and 60°Brix may be induced by a sharp increase of the viscosity of the tea concentrates, which helped to improve the stability of tea concentrate. It may be indicated that the stability of green tea concentrate enhanced when the concentration higher than 50°Brix, which helped to restrain the formation of tea cream.

Ice Cream: Foam Formation and Stabilization—A Review

Ice cream has been studied from ingredients to process conditions, ice crystal formation to ice crystal growth, and ingredient selection to eating quality. One of the key aspects of ice cream is air cells, as formation and acceptance of ice cream rely on foam production and stabilization. Air cells in ice cream provide a unique structure that governs many of this product's keeping and eating qualities. The air cells are dependent upon ice cream mix composition (fat, protein, and surface active ingredients) as well as processing conditions (freezer shear force, hardening time, and storage temperatures). Optical, low-temperature scanning electron microscopy and transmission electron microscopy are applied to observe the morphology and size of air cells in ice cream. Air cells are crucial in forming the product and for eating quality and enjoyment.

Cream formation and main chemical components of green tea infusions processed from different parts of new shoots

The formation of green tea cream and its chemical components were investigated. The green tea infusions were processed from different parts of new shoots: the bud and the first leaf, the second leaf and its implicative stem, the third leaf and its implicative stem, and the fourth leaf and its implicative stem, which were named as first part, second part, third part and fourth part, respectively. The results showed that the formation of tea cream and its settlement slowed down gradually from the first part to the fourth part, and that the amount of tea cream also decreased accordingly. The amount of tea cream was influenced remarkably by the chemical components in the green tea infusion. The main components of green tea cream were polyphenols (29.86 –78.66%), total sugar (14.47–27.62%) and caffeine (2.35–10.43%). Catechins (12.8–42.5%) were the main components of polyphenols which participated in tea cream formation. The main components in the catechins were found to be (−)-epigallocatechin (EGC), (−)-epigallocatechin gallate (EGCG), (−)-epicatechin (EC) and (−)-epicatechin gallate (ECG). Seven minerals were found in the tea cream, including Ca 2+, K +, Mg 2+, Mn 2+, Na +, Zn 2+ and Ni 2+.

Effect of tannase treatment on protein–tannin aggregation and sensory attributes of green tea infusion

Effect of tannase enzymatic treatment on protein–tannin aggregation and sensory attributes of green tea infusion was investigated. Green tea leaves were extracted with hot water at 85 °C for 20 min, the tea infusion was then treated with tannase. Results showed that both EGCG and ECG of the tea catechins were hydrolyzed by tannase into EGC and EC, respectively, accompanied by production of gallic acid. The tannase-treated tea infusion had a relatively lower binding ability with protein. Changes in the content of tea catechins, formation of tea cream, and turbidity of tea infusion with or without tannase treatment were measured after 4 weeks. Content of catechins in the tannase-modified tea remained almost unchanged, while those without tannase treated (control) decreased significantly ( p < 0.05). Meanwhile, better color appearance and less tea cream formation were observed for the tannase-treated green tea, and tea cream formed for the control after storage. Results of the sensory evaluation showed that mouth feeling, taste and the overall acceptance of the tannase-treated green tea infusion were all better than those of the control.

NMR assessment of mix and ice cream. Effect of formulation on liquid water and ice

Abstract The overall quality of ice creams is often related to the state of water and fat either in liquid or solid state. This work investigates the capacity of low-field NMR spectrometry in characterizing the different behaviours of water protons in mix and in ice cream. Meanwhile, different formulations (types of protein, fat or emulsifier) were tested. The factor which most affected the T 2 and T 1 relaxation time of the liquid water and ice protons was the protein type. Although this effect is well-known on the NMR behaviour of liquid water protons, it has been observed on the solid water protons for the first time. Assessing the behaviour of liquid water already gave new elements for better understanding the mechanisms responsible for the formation and aging of mix and ice cream. The corresponding relaxation time showed no correlation with rheological properties of mixes, indicating that interactions between molecules in suspension (e.g. proteins) and water protons are not involved in. Its changes during cold storage were relevant of a “non-equilibrium” behaviour, which is further discussed in the paper.

Kinetics of Cream Formation by the Mechanism of Consolidation in Flocculating Emulsions

In this work we propose a theoretical description of the process of creaming of batch emulsions when a sharp boundary exists between a clear serum phase and the sedimenting drops. The creaming is represented as a continuous consolidation of partially aggregated network. The treatment reproduces correctly the trend for gradually decreasing rate of sedimentation as time goes on. The theoretical results are compared quantitatively with experimental measurements of the creaming rate. Oil-in-water systems, stabilized by proteins (β-lactoglobulin (BLG), bovine serum albumin, and mixtures BLG+β-casein) were investigated. Faster creaming is attributed to larger size of the sedimenting objects (flocs of emulsion droplets). In systems obeying the creaming mechanism with sharp boundary (SB) the flocs are smaller when the protein concentration is higher. This supports the hypothesis for the stabilizing role of the excess amount of protein (forming lumps and multilayers on the interface). Theoretical analysis demonstrates that the formation of flocs by gravitational coagulation is a much faster process than the consolidation of the cream. Hence, the dispersions first flocculate and then cream. With increasing β-casein content in mixtures BLG+β-casein the emulsions depart from the SB-type behavior and are characterized by the presence of small nonflocculated droplets, which do not sediment (the serum is turbid and the boundary with the concentrated dispersion is diffuse, DB behavior). This is connected with hindered flocculation, perhaps due to β-casein's augmented ability to prevent droplet aggregation.

The self-association of the black tea polyphenol theaflavin and its complexation with caffeine

Caffeine is found in both coffee and tea whilst polyphenols are present in a wide variety of foods and beverages. Theaflavin and its gallate esters are polyphenolic molecules which can be isolated from black tea infusions. The theaflavin family of polyphenols contribute to the taste and colour of tea, and their complexation with caffeine is thought to be largely responsible for the formation of tea cream, a precipitate that forms as tea cools. The self-association of theaflavin and caffeine was studied using nuclear magnetic resonance methods (chemical shift changes and self-diffusion constants on dilution) and it is shown that caffeine forms stacks of molecules (Ks = 7.9 l mol−1 at 300 K), while theaflavin forms stable dimers (Ks = 230 l mol−1). The theaflavin monomer consists of a planar benzotropolone ring system, with the two flavan rings approximately orthogonal to this plane, and stacked against each other. In the dimer, two benzotropolone rings align with an antiparallel geometry. Two molecules of caffeine bind to one molecule of theaflavin in a strictly sequential manner, with first and second association constants of 11.9 and 16.5 l mol−1, respectively. It is proposed that the first caffeine inserts between the two flavan rings, and the second then binds to the newly liberated flavan surface.