SHELF-LIFE of SPRAY-DRIED INFANT FORMULA SUPPLEMENTED WITH LACTULOSE

Storage studies were carried out to assess the stability of a lactulose-containing infant food formula (II) in comparison with a control formula (I) at, 5, 27 and 38C up to 20 weeks. Products were packed in tinned containers and sealed in nitrogen. No changes were observed in moisture and solubility of formulas I or II at any temperature-time combination. Lactulose levels increased during storage, while available lysine decreased to a similar extent in both formulas. Hydroxymethyl furfural content increased during storage, while the whiteness of both formulas remained unaffected. Addition of lactulose did not influence the acceptability of the product, but there was a correlation between the increase in free fatty acid levels and the decrease in acceptability scores. the study indicated that addition of lactulose did not alter any storage characteristic of the product and that the product with added lactulose was acceptable up to 16 weeks of storage at all temperatures.     

STRUCTURED LIPIDS: ACIDOLYSIS OF GAMMA-LINOLENIC ACID-RICH OILS WITH n-3 POLYUNSATURATED FATTY ACIDS

Structured lipids were synthesized by acidolysis of γ-linolenic acid-rich oils and n-3 polyunsaturated fatty acids (PUFA), namely eicosapentaenoic acid (EPA; 20:5n-3) and docosahexaenoic acid (DHA, 22:6n-3), using different lipases. Lipase PS-30 from Pseudomonas sp. was chosen over the other enzymes to catalyze the acidolysis reaction owing to higher incorporation of n-3 PUFA. Effects of mole ratio, reaction time, incubation temperature, enzyme load, and solvent type on acidolysis reactions were studied. At 250 enzyme activity units, incorporation of n-3 PUFA reached optimal values of 29.9 and 30.7% for the reactions with borage and evening primrose oils, respectively. For the time course reaction, incorporation of n-3 PUFA increased up to 34.1 and 31.5% (in 30 h), in borage and evening primrose oils, respectively. After 24 h incubation in hexane, n-3 PUFA (EPA+DHA) incorporated into borage and evening primrose oils was 31.8 and 32.7%, respectively. The highest n-3 PUFA incorporation in both oils occurred at a mole ratio of 1:2:2 (oil/EPA/DHA). Among the solvents tested, n-hexane was found to be highly effective; total n-3 PUFA incorporation of 33.3 and 27.8% in borage and evening primrose oils, respectively, was achieved in hexane. However, the solvent-free reaction afforded products with a total of 23.4–28.8% n-3 fatty acids (EPA and DHA).     

EXTENDING SHELF LIFE OF UHT CREAMS

The effect of additives and changes of composition on the shelf life of UHT creams was examined. All changes investigated with the exception of added lecithin, showed some improvement in cream feathering properties. Marked improvement with shelf life extended to at least six months was, however, only found with addition of sodium caseinate (30 g/l) and reduction of calcium activity, the latter being achieved either by removal with ion exchange resins or by immobilization with citrate and carbonate.     

栅栏技术延长牦牛腱子制品货架期的应用研究

通过对牦牛腱子加工过程中原料、辅料、各加工工序及用具中微生物消长情况的研究,在危害分析关键控制点（HACCP）的基础上,应用栅栏技术（HT）控制微生物,提高成品率,延长产品的货架期.     

PHYSICOCHEMICAL PROPERTIES OF EUROPEAN BAKERY MARGARINES WITH AND WITHOUT TRANS FATTY ACIDS

Physicochemical properties of commercially available European bakery margarines (cream margarines, cake margarines [CM] and puff pastry margarines [PPM]) containing and devoid of trans fatty acids (TFAs) were investigated. Studied physical properties were the solid fat content (SFC), dropping points (DPs), polymorphism, texture (hardness), plasticity and the melting profile by differential scanning calorimetry. Experimental results confirm that physical properties of the margarines corresponded with their application area. For example, SFC and DPs of PPM were higher than cream margarines and CM; they were also harder at 15C. Moreover, all the investigated physical properties were affected by the suppression of TFA in bakery margarines .

PRACTICAL APPLICATIONS

This study has shown that margarines present different physical properties with respect to their purposed application but also highlight changes that appear due to the absence of trans-fatty acids in the formulations. These changes can really affect the bakery abilities and will, finally, influence the quality of the bakery products.     

EFFECTS OF ANTIOXIDANTS AND PROCESSING ON STABILITY OF MUSCLE FROM HYBRID STRIPED BASS WITH OMEGA-3 FATTY ACIDS

Hybrid striped bass were fed four diets containing 0, 4, 8, and 12% menhaden fish oil (MFO) for 18 weeks during final growth to determine (1) omega-3 (n-3) fatty acid uptake and its effect on fish and postharvest quality, and (2) the effects of selected antioxidants on oxidation and sensory quality of fish enhanced with n-3 fatty acids. Lipid content was significantly higher in the two highest MFO treatments: 3.2, 3.5, 3.9 and 4.4% in the 0, 4, 8 and 12% MFO treatments, respectively. During this study EPA(eicosapentaenoic acid) significantly increased with increasing dietary MFO: 5.4 ± 0.93, 6.9 ± 0.15, 8.0 ± 0.45 and 8.1 ± 0.35 for the 0, 4, 8 and 12% MFO diets, respectively. The following fatty acids in muscle increased 1% or more in fish fed 12% MFO compared to fish fed 0% MFO: 14:0, 16:1n-7, 22:6n-3, and total polyunsaturates, total n-3, and the n-3/n-6 ratio. Changes in individual fatty acids in fish muscle reflected the concentrations of fatty acids in the diet. Hybrid striped bass fed 8 and 12% MFO had twice as much n-3 fatty acids (1.0 g/100 g tissue) as fish cultured on diets without MFO     

ANALYSIS OF LONG-CHAIN FATTY ACIDS IN BEER

A simple gas chromatographic method is presented for quantitative analysis of long-chain fatty acids in beer. Analytical results are quoted for ten different beers.     

MICROALGAE AS A SOURCE OF FATTY ACIDS

Microalgae are a very diverse group of organisms that consist of both prokaryotic and eukaryotic forms. Although most microalgae are phototrophic, some species are also capable of heterotrophic growth. Some species of microalgae can be induced to overproduce particular fatty acids through simple manipulations of the physical and chemical properties of the culture medium. As a result of the profound differences in cellular organization and growth modes and the ability to manipulate their fatty acid content, microalgae represent a significant source of unusual and valuable lipids and fatty acids.
The utilization of microalgal lipids and fatty acids as food components requires that these organisms be grown at large scale under controlled conditions. Several growth systems have been developed for large scale growth of phototrophic microalgae using either natural sunlight or artificial light, but their lack of control of culturing parameters or their high cost of operation have limited their utility for the production of food products. Instead, large scale cultivation of heterotrophic microalgae using classical fermentation systems provides consistent biomass produced under highly controlled conditions at low cost.
Microalgae contain many of the major lipid classes and fatty acids found in other organisms. However, they are also the principal producers in the biosphere of some polyunsaturated fatty acids, especially docosahexaenoic acid (DHA). The high DHA content found in some algae is currently being utilized to supplement infant formula to enable it to more closely resemble human breast milk. Thus, the commercialization of DHA from microalgae demonstrates the value of these organisms as a source of useful fatty acids.     

THE EFFECT OF ANTIOXIDANTS ON THE KEEPING QUALITY OF SPRAY-DRIED WHOLE MILK POWDER

Spray-dried whole milk powders containing either 0.01 per cent ascorbyl palmitate or this compound plus 0.01 per cent citric acid were prepared and their keeping quality under accelerated storage conditions at 37°C compared with control powders and powders containing dodecyl gallate. Ascorbyl palmitate alone afforded little protection against oxidative deterioration but together with citric acid considerably improved keeping quality. Although the addition of several antioxidants to edible oils and fats and butter intended for manufacture is permitted, their addition to milk powder is forbidden (Regulations, 1966). There are several reasons for this discrimination, the chief of which lies in the phenolic nature of the most effective antioxidants in spray-dried whole milk powder (Findlay, Smith & Lea, 1945). More recently ascorbyl palmitate has been used to delay the onset of oxidation in butter (Koops, 1964) and milk fat (Englelhardt & de Man, 1963). It seemed appropriate therefore, despite the different chemical composition and physical condition of the fat in butter and in milk powder, to examine its effectiveness in the latter product. In the quantity employed (0–01 per cent), ascorbyl palmitate would not present a risk to health, and its usefulness could probably be enhanced by the addition of a simple synergist such as citric acid, known to be effective with dodecyl gallate in lard (Lea, 1958).