CHANGES IN COOKING AND TEXTURAL PROPERTIES OF SPAGHETTI COOKED WITH DIFFERENT LEVELS OF SALT IN THE COOKING WATER

The effect of cooking water on textural and cooking properties of spaghetti was examined using four different salt concentrations 0, 1, 2, 3 and 4% in the cooking water and two types of spaghetti. Brand A was normal durum wheat spaghetti and brand B was spaghetti enriched with bran. Regardless of the cooking water used, brand B was harder, less sticky than brand A and it absorbed less water. Brand A required less cooking time. As salt concentration increased cooking time and hardness scores increased. Adhesiveness values were highest at the early stages of cooking and declined as cooking time increased.     

THE MILLING ENERGY OF MALTED BARLEY AND ITS RELATIONSHIP WITH HOT WATER EXTRACT AND α-AMYLASE ACTIVITY

Hot water extract is dependant on endosperm structure and its breakdown during malting. These endosperm characteristics can be rapidly assessed on 5 g samples by measuring the milling energy of malted barley. α-amylase determinations on the resultant flour indicate that good malting barleys have either moderate or high levels of the enzyme. High levels of α-amylase will not confer good malting quality where endosperm modification has proceeded slowly.     

OPTIMIZATION STUDY FOR THE PRODUCTION OF CITRIC AND GLUCONIC ACID FROM FIG WATER EXTRACT BY ASPERGILLUS NIGER IN SURFACE FERMENTATION

The production of citric and gluconic acid from fig extract by Aspergillus niger ATCC 10577 and A. niger B60 in surface fermentation was investigated. The strain 10577 gave higher concentration of citric and gluconic acid than strain B60. A maximum citric and gluconic acid concentration (20.5 and 97.0 g/L, respectively), citric acid yield (12%), biomass dry weight (18.5 g/L), and sugar utilization (85%) was achieved at an initial sugar concentration of 200 g/L and a pH of 7.0. On the other hand, the highest gluconic acid yield (79.7%) was obtained in culture grown at initial sugar concentration 100 g/L. The addition of 4% (v/v) methanol in the fig extract increased the concentration of citric and gluconic acid from 20.5 and 97.0 g/L to 30.7 and 145.5 g/L, respectively. Citric acid was separated from the gluconic acid by extraction with diethyl ether or ethyl acetate.     

KINETIC BEHAVIOR OF SOYBEAN LIPOXYGENASE: A COMPARATIVE STUDY OF THE FREE ENZYME AND THE ENZYME IMMOBILIZED IN AN ALGINATE SILICA SOL‐GEL MATRIX1

Lipoxygenase (LOX) is an enzyme that regioselectively introduces a hydroperoxide into polyunsaturated fatty acids (PUFA). We recently reported a procedure that immobilizes soybean LOX within an alginate sol‐gel matrix. In this study, the kinetic profile of free LOX was compared with that of the sol‐gel immobilized LOX. The temperature dependent activity profile of free LOX was optimal at 25C whereas immobilized LOX had optimal activity over the temperature range of 25–35C. Enzyme activity, measured in aqueous buffer, for both the free and immobilized LOX preparations had K_m values of 2.5 and 1.40 mmoles/L, respectively, and V_max values of 0.056 and 0.02 μmol/min, respectively. The relative rates of oxidation of linoleic acid and acylgfycerols containing linoleoyl residues catalyzed by free and immobilized LOX also were determined The results showed that both free and immobilized LOX favor linoleic acid as a substrate. Relative substrate preference for free LOX was linoleic acid >1‐monolinolein > 1,3‐dilinolein >trilinolein, and for immobilized LOX was linoleic acid >l, 3‐dilinolein >1‐monolinolein >trilinolein. In general, LOX immobilized in alginate silica sol‐gel matrix retained the physical and chemical characteristics of free LOX.     

27—THE RôLE OF WATER IN THE SETTING OF WOOL: A STUDY OF SETTING AT TEMPERATURES ABOVE 100°C: PART II: FABRIC PROPERTIES

An account is given of a study of the changes in fabric properties caused by setting with steam in autoclaves. Dimensional stability, shear angles, thickness, and breaking strength were measured, and the influence of variations in setting conditions, such as humidity, temperature, time, pH, and mechanical pressure, was investigated. The controls necessary for eliminating end-to-end effects in whole pieces are discussed.     

EFFICACY OF SOUR WHEY AS A SHELF‐LIFE ENHANCER: USE IN ANTIOXIDATIVE EDIBLE COATINGS OF CUT VEGETABLES AND FRUIT*

ABSTRACT

The effectiveness of edible coatings containing sour whey powder (SWP), compared with soy protein isolate (SPI) and calcium caseinate (CC), in reducing oxidative browning and moisture loss during storage (4C) of cut apples, potatoes, carrots, and onions was investigated. Oxidative discoloration, as determined by the Commission Internationale de I'Eclairage L*a*b* color scale, was significantly reduced (P < 0.05) by treatments over a storage time of 120 min. Loss of lightness was reduced by CC, SPI and SWP coatings. These respectively showed 2.7, 3.3 and 1.5% change of L* value in coated apples as compared with 7.4% in the control. Browning in cut potatoes was significantly reduced from a 145.1% increase in the a* value of the control to 45.9, 37.0 and 30.3% increase for CC, SPI and SWP treatments, respectively. The b* values also reflected the effectiveness of SWP. The moisture barrier effect, tested over a period of 5 days at 4C, was significantly better for the treatments than control. SWP was the best and significantly reduced moisture loss in potatoes and carrots by 40 and 59%, respectively, over control. Cut onions did not show any treatment effect both in terms of off‐color development and moisture loss. The reasons for the excellent moisture barrier and antioxidative property of SWP were discussed.

PRACTICAL APPLICATIONS

Oxidative degradation of fresh fruits and vegetables is a major problem faced by the industry today. Most of the fresh produce is grown in the southwestern part of the country, requiring days of transportation to retail outlets. As the educated consumer is highly health conscious, any effort in extending the shelf life will have to be nonchemical, and preferably natural. Because of small profit margins, the intervention must also be inexpensive. Millions of MT of sour whey, a by‐product of cottage whey manufacture, is wasted because of the lack of appropriate food applications. It is natural, nutritious and presently very inexpensive. Our research investigated the possibility of using this by‐product as a final wash to enhance the so‐called window of freshness of fresh produce and fruit.