Fruits frozen

A combined technique has been developed for the preparative isolation of anthocyanins from blackcurrant (Ribes nigrum) fruits. Frozen berries (370 g) were extracted three times with 11 of methanol containing 0.1 per cent TFA at 4°C for 6 h. The combined exracts were concentrated, diluted to 250 ml with water and extracted with ethyl acetate. The aqueous phase was concentrated to 100 ml and applied in an ion-exchange column. The column... 

As a general rule, foods which are not to be frozen are handled and stored at a temperature just above their freezing point, providing this does no damage (exceptions are fruits such as bananas and lemons). Produce which is to be frozen must be taken down below the freezing point of the constituents. Since foodstuffs contain salts and sugars, the freezing process will continue down to -18°C and lower. 

Afewitems, strawberries, other soft fruits and pieces of cauliflower, are quick-frozen with liquid nitrogen. 

Frozen fruit and vegetables will be sealed in plastic bags and stored at -18°C or lower. The humidity at this temperature is not important. 

The successful and profitable control of frozen food quality requires workable standards of product quality and condition and suitable methods for determining the degree of product conformance with standards. The frozen fruit and vegetable industry has developed rapidly during the past 20 years and serious concentration upon the development of adequate standards and objective methods for quality measurement is necessary. Such standards and methods should be placed on a uniform basis the country over and given official and legal status. 

Because of their highly perishable nature, frozen fruits and vegetables are very sensitive to mishandling during distribution, especially in connection with maintaining proper conditions of temperature. 

Much valuable research has been devoted to developing the basic principles for the production of frozen fruits and vegetables of high and uniform quality. If this knowledge could be applied to its fullest extent, there would be little need for concern over the quality of such foods. Before this can be done, those responsible for quality control must be provided with suitable standards of quality and condition, and objective methods of analysis which will clearly indicate conformance or nonconformance to the standards. Responsibility for this resides with the research food technologist or chemist. It constitutes a rich field for profitable and practical research. 

There is yet much to be done in establishing standards and objective methods in which one may have complete confidence. The frozen fruit and vegetable industry has developed rather rapidly during the past 20 years and it is now time for individuals and organizations responsible for the conduct of frozen food research to concentrate... 

I know. Frozen drinks are bimbos. What is the cocktail version of a sexist remark The Lucy Colada has coconut cream in it, too, to keep your self-respect from returning anytime soon.The bartender served it in a Mexican beanpot-shaped goblet he floated the dark rum on the top of the cream-colored drink. You stir it in with a straw. It s dessert, but it s tasty. Passion fruit steels it up with acidity. 

Frozen Foods. Corrosion caused by the reaction of foods with aluminum containers is unusual if the products are handled and stored at 0°F or lower. However, the inevitable bad handling of frozen foods during commercial distribution causes undesirable thawing. In this condition, not only does the food deteriorate, but it can also attack the container. Such unwanted reactions can be effectively controlled by using coated aluminum containers. Since aluminum is highly compatible with frozen fruits and citrus juices, it has been used extensively as a liner for fiberboard composite cans, as complete aluminum cans, or as ends in combination with steel can bodies in the frozen food industry. 

Ascorbic acid is added to many foods for its nutritive value. It is used extensively as an antioxidant to prevent flavors and colors from being damaged by oxidation. It is often used in canned or frozen fruits to prevent the browning that accompanies oxidation. While not as powerful an antioxidant as sodium bisulfite, it has a better nutritional reputation. 

Neotame is used in tabletop sweeteners, frozen desserts, chewing gum, candy, baked goods, fruit spreads, and ready-to-eat cereals. 

ANCos B DE, GONZALES E M and CANO M p (2000) Ellagic acid, vitamin C, and total phenolic contents and radical scavenging capacity affected by freezing and frozen storage in raspberry fruit , J Agric Food Chem, 48 (10) 4565-70. 

For stone fmit, e.g., olive cherries, where the mature fruit is analyzed, the stone should be removed, and the weight of pulp and stone should be recorded. The residue is calculated on the basis of whole fruit. This step can be done either in the field prior to the fruit being frozen, which makes the procedure easier, or in the analytical laboratory. In either case, care needs to be taken to avoid cross-contamination. 

The juice is recovered by inserting tubular knives into the fruit and squeezing the fruit. Alternatively, the fruit may be cut in half and squeezed. The recovered juice is put through a finisher to remove a portion of the pulp sacs, is heated to inactivate enzymes, and is either bottled as single-strength juice or concentrated for frozen concentrate. 

SFE of fruits and vegetables and meat products has been reported, but the sample preparation techniques necessary to obtain reproducible results are extremely time consuming. Solid absorbents such as Hydromatrix, Extrelut " anhydrous magnesium sulfate or absorbent polymers are required to control the level of water in the sample for the extraction of the nonpolar pesticides. Without the addition of Hydromatrix, nonpolar pesticides cannot penetrate the water barrier between the sample particles and the supercritical CO2. The sample is normally frozen and the addition of dry-ice may be required to reduce losses due to degradation and/or evaporation. Thorough reviews of the advantages and limitations of SFE in pesticide residues... 

Alkylenebis(dithiocarbamates) are not stable and decompose on contact with acidic fruit and vegetable juice generated during the sample preparation. The sample preparation is a critical step in their determination. The homogenization should be made with frozen samples as rapidly as possible followed immediately by the analysis. 

Pyrimidifen residues in fruits such as apple and orange are stable (>90%) after frozen storage for 2 months. 

Food products may include frozen produce, canned produce, pasta, sauces in jars, prepared meals or pizzas. It is important to work closely with the manufacturer, in working out the best types of ingredients to use, depending on the manufacturing facilities available. For example, frozen fruit and vegetable processors require a specific size and quality, pasta and bread manufacturers will have their specific requirement of the variety and grade of wheat. They require consistent quality and volume so as to be able to produce a consistent end product. As with restaurants, it is important to build a good relationship with your processor and to keep the manufacturer informed of any potential problems. This allows them to take other action to ensure their production does not suffer. 

Hassimotto NMA, Genovese MI and Lajolo FM. 2005. Antioxidant activity of dietary fruits, vegetables, and commercial frozen fruit pulps. J Agric Food Chem 53(8) 2928-2935. 

Figure 2.3 illustrates a process in which the outer layer of a product is quickly frozen as a congealed crust. These CRUSToFREEZE plants have a capacity between 1500 and 5000 kg/h and require 0.5 to 0.8 kg LN2 pro kg of product, which has to be frozen totally on a conveyor belt. Figure 2.4 shows the product exit of the plant in Fig. 2.3. The freeze drying of coffee and tea extracts, fruit pulps or small pieces of meat require a multi- stage pretreatment. The granulated end product from coffee and tea extracts should have a defined grain size, a desired color, and a predetermined density. Fruit pulps should become granulated, with the appearance of fruit pieces, while meat pieces should not stick together like a small meat ball, but be recognized as single pieces when presented in a meal.

The people of London and Paris in Victorian times (the second half of the nineteenth century) were always keen to experience the latest fad or novelty, just like many rich and prosperous people today. And one of their favourite new inventions was ice cream and sorbets made of frozen fruit. 

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