LIPID CONTENT AND FATTY ACID COMPOSITION IN THE GREEN-LIPPED MUSSEL PERNA VIRIDIS (L.)

The lipid content and fatty acid profile in soft tissue of the green-lipped mussel Perna viridis, a widely distributed tropical and subtropical bivalve species, were investigated. The total and neutral lipid contents were 6.17 ± 0.71 and 2.71 ± 0.42 mg per 100 mg dw, respectively. The content of docosahexaenoic acid (DHA, C22:6n-3) was 24.38 ± 2.50 mg/g dw whereas eicosapentaenoic acid (EPA, C20:5n-3) was present at 12.29 ± 2.12 mg/g dw. These two fatty acids were also at the top high percentage among all the fatty acids, with 38.06 ± 0.86% and 17.89 ± 1.24% (w/w) in total lipids and 34.64 ± 2.74% and 20.33 ± 1.05% (w/w) in neutral lipids, respectively. Therefore, green-lipped mussel is a rich source of DHA and EPA, the two n-3 polyunsaturated fatty acids that are beneficial to human health and nutrition.     

OCCURRENCE OF POTENTIALLY PATHOGENIC VIBRIOS IN BIVALVE MOLLUSCS (MUSSELS AND CLAMS) FROM RETAIL OUTLETS IN THE NORTH OF SPAIN

Forty-three samples of shellfish (22 mussels and 21 clams) purchased from retail outlets from February through October were tested for the presence of vibrios associated with human disease . Vibrio spp. was found in 51.16% of the samples . V. alginolyticus was the commonest Vibrio species found in the samples, followed by V. parahaemolyticus, V. fluvialis and V. cholerae non-01. All V. parahaemolyticus isolated were Kanagawa-phenomenon negative. Hemolytic activities were shown in all isolates of V. fluvialis and V. cholerae. Bacterial indicators of quality and safety were within permitted limits by authorities. The results indicate the potential risks of food poisoning associated with the consumption of raw or undercooked shellfish .     

PREDICTION OF TEXTURE IN GREEN ASPARAGUS BY NEAR INFRARED SPECTROSCOPY (NIRS)

NIR spectroscopy was used to estimate three textural parameters of green asparagus: maximum cutting force, energy and toughness. An Instron 1140 Texturometer provided reference data. A total of 199 samples from two asparagus varieties (Taxara and UC‐157) were used to obtain the calibration models between the reference data and the NIR spectral data. Standard errors of cross validation (SECV) and r² were (5.73, 0.84) for maximum cutting force, (0.58, 0.66) for toughness, and (0.04, 0.85) for cutting energy. The mathematical models developed as calibration models were tested using independent validation samples (n =20); the resulting standard errors of prediction (SEP) and r² for the same parameters were (6.73, 0.82), (0.61, 0.57) and (0.04, 0.89), respectively. For toughness, substantially improved r² (0.85) and SEP (0.36) when four samples exhibiting large residual values were removed. The results indicated that NIRS could accurately predict texture parameters of green asparagus.     

A NONDESTRUCTIVE TEST FOR DETERMINATION OF OPTIMUM MATURITY OF FRENCH (GREEN) BEANS (Phaseolus vulgaris)1

Optimal maturity stage of Burpee Stringless Variety of French (green) beans was determined by a trained sensory panel using beans harvested at definite intervals of growth till over-maturity. Of the changes in ten physico-chemical characteristics studied during growth, weight to length (W/L) ratio is closely related to the sensory characteristics and can be used as a simple non-destructive test for determining the optimal maturity. The beans are very tender up to a W/L ratio of 0.4 g/cm, tender from 0.41 to 0.5 g/cm which is optimal mature stage, mature from 0.51 to 0.6 g/cm, and over-mature thereafter. The maximum force required to cut the bean by placing on its edge or flat in the triangular slot of the Warner-Bratzler shear press was 9.0 kg in tender beans and could be made use of as an instrumental method for determining the maturity. The force required to cut the beans edgewise was more than in the flat position at or before the optimal maturity and the values reversed thereafter. Changes in total solids, alcohol insoluble solids and fibrous matter contents between tender and mature ones are too sudden and large during the short transition period for being used as objective method(s) but yielded meaningful data when considered along with W/L ratio or shear force.     

RESIDENCE TIME DISTRIBUTION IN HORIZONTAL THIN FILM SCRAPED SURFACE HEAT EXCHANGER (SSHE)

The residence time distribution (RTD) studies were conducted to predict the flow characteristics in thin film SSHE. the experiments were conducted at zero heat flux using water as working fluid. A pulse input in form of saturated sodium chloride solution was used as the disturbance at inlet and the response in form of electrical conductivity was measured at outlet. Thirty-two trials were conducted at different flow rates, number of blades and rotor speeds. the E-curves were plotted. It was inferred that the flow in thin film SSHE approximates to plug flow. Also, as the mass flow rate increased, RTD improved. the increasing number of blades resulted in appreciable improvement in RTD. the rotor speed had similar effect as that of number of blades on RTD. However, the number of blades had more profound effect as compared to rotor speed. If the rotor design is modified then RTD can be improved and simultaneously the power consumption can be kept at minimum.     

KINETICS OF HEAT/ENZYMIC DEGRADATION OF ASCORBIC ACID IN FLUTED PUMPKIN (Telfairia occidentalis) LEAVES

Thermal/enzymic degradations of ascorbic acid in whole, chopped and pureed fluted pumpkin leaves were studied from 60 to 100C (5–60 min). Degradation of ascorbic acid followed first order kinetics with the rate constants having maximum values at 80–90C. Ascorbic acid degradation exhibited strong deviation from linearity in thermal resistance, Arrhenius and absolute reaction rate plots at 100C indicating inactivation of the oxidative enzymes around 90C. At lower temperatures (60–90C) ascorbic acid was more stable in the whole and chopped leaves than in the pureed system. Activation energies ranged from 49 to 50.8 KJ mol⁻¹. At 100C, the puree matrix offered more protection to ascorbic acid.     

POTASSIUM HYDROXIDE REPLACEMENT FOR LYE (SODIUM HYDROXIDE) IN TOMATO PEELING

Lye (sodium hydroxide [NaOH]) peeling is the most common method for peeling tomatoes in the Midwest U.S. With the rise in the cost of NaOH and the associated disposal problems, alternative methods for peeling need to be examined. Solutions of NaOH, potassium hydoxide (KOH) and calcium hydroxide (Ca[OH] ₂ ) at different concentrations were compared to determine their efficacy as peeling agents. Ca(OH) ₂ was ineffective as a peeling agent because of its low solubility. KOH produced peeling equivalent to NaOH, but at half the normality. A lower normality is needed because of the increased reactivity of KOH compared to NaOH. This is further demonstrated by the addition of salts to the solution. The use of KOH instead of NaOH may result in cost savings and decreased waste disposal problems.     

MODIFICATIONS IN THE MINERAL CONTENT OF GREEN ASPARAGUS (ASPARAGUS OFFICINALIS, L.) DURING DEVELOPMENT AND PROCESSING (BLANCHING AND CANNING)

Five commercial sizes of green asparagus (fine, middle, thick, very thick and extra thick) were examined at different stages of commercial treatment (blanched and canned) to study possible changes in six minerals (Cu, Zn, Fe, Mn, Ca and Mg) and the ash content. Significant changes were only found in the Fe and Mg content in washed asparagus of different commercial sizes. Blanching must be considered a moderate step because it only modified the levels of the Fe and Ca in some sizes. Canning, however, resulted in a leaching of Cu, Zn, Mn, Fe and Mg, and the up-take of Ca. The size of green asparagus was a source of variation in the Mn, Fe and Ca contents after canning. The highest gains after canning for Ca were detected in the biggest sizes.     

EVALUATION OF RED CURRANTS (RIBES RUBRUM L.), BLACK CURRANTS (RIBES NIGRUM L.), RED AND GREEN GOOSEBERRIES (RIBES UVA-CRISPA) FOR POTENTIAL MANAGEMENT OF TYPE 2 DIABETES AND HYPERTENSION USING IN VITRO MODELS

Red currants (Ribes rubrum L.), black currants (Ribes nigrum L.), red and green gooseberries (Ribes uva-crispa) were evaluated for the total phenolics, antioxidant capacity based on 2, 2-diphenyl-1-picrylhydrazyl radical scavenging assay and functionality such as in vitro inhibition of α-amylase, α-glucosidase and angiotensin I-converting enzyme (ACE) relevant for potential management of hyperglycemia and hypertension. The total phenolics content ranged from 3.2 (green gooseberries) to 13.5 (black currants) mg/g fruit fresh weight. No correlation was found between total phenolics and antioxidant activity. The major phenolic compounds were quercetin derivatives (black currants and green gooseberries) and chlorogenic acid (red currants and red gooseberries). Red currants had the highest α-glucosidase, α-amylase and ACE inhibitory activities. Therefore red currants could be good dietary sources with potential antidiabetes and antihypertension functionality to compliment overall dietary management of early stages of type 2 diabetes.     

STUDIES OF RETARDING AGENT FOR DECREASING STARCH RETROGRADATION IN WANKAO (RICE CURD)

ABSTRACT

WanKao (rice curd) products, included control and added pregelatinized waxy rice flour (PWRF) retarding agent, were prepared and evaluated by texture profile analysis and sensory evaluation. The results showed that the amylose complexing index of the WanKao products contained PWRF were higher than the control, and directly added α‐amylase or monoglycerides. Upon storage, WanKao products contained PWRF showed higher water activity and starch digestibility than those added α‐amylase or monoglycerides. The hardness and soluble starch content of WanKao products contained PWRF were significant lower than those of added α‐amylase or monoglycerides and the control. The WanKao products added PWRF also exhibited softer texture during storage. For sensory evaluation, the higher score of was the added PWRF‐D (contains 100 g of waxy rice flour, 200 g of water, 6% of monoglycerides and 400 mg/kg of α‐amylase) WanKao product presented higher overall acceptability than that of added α‐amylase, monoglycerides, and control either fresh or after low‐temperature storage (5C for 5 days). As a result, the texture qualities of WanKao could be improved by the addition of the PWRF and also the staling and retrogradation rates were further retarded.

PRACTICAL APPLICATIONS

Taiwan's consumers demand for high quality WanKao products, i.e., softer, slow to staling and retrogradation, and good acceptability. Our results indicated that the qualities of WanKao could be improved by the addition of the novel retarding agent, PWRF, and the staling and retrogradation rates were further retarded.     

RHEOLOGICAL MODELS FOR DISPERSIONS OF POLYOXYETHYLENE (4) LAURYL ETHER IN HYDROXYETHYL CELLULOSE

Viscometric properties of polyoxyethylene (4) lauryl ether (Brij 30) in hydroxyethylcellulose (HEC) dispersions were evaluated over a concentration range of 2.0–3.5% HEC and 0–16% Brij 30. Three rheological models: the modified Shangraw structure equation, the Steiger-Trippi-Ory equation and the power-law model were fitted to the data and found to describe accurately the flow behaviour of the dispersions at 30.0°C between shear rates of 8.5–685 s^-1. Variation of model parameters with surfactant (Brij 30) concentration was computed for each HEC dispersion. A shear sensitive interaction between the surfactant and the cellulose polymer was noted.     

PRESERVATION OF "UMBU" (SPONDIAS TUBEROSA ARRUDA CÂMARA) PULP IN THE GREEN STAGE OF MATURATION BY COMBINED METHODS

“Umbu” (Spondias tuberosa Arruda Câmara) is a typical fruit from northeastern Brazil of considerable economic importance to this region, because several products are derived from it and commercialized, especially the pulp, which can be used as a raw material for preserves and juices. The objective of this research was to study the preservation of umbu in the green stage of maturation by combined methods, including heat treatment and the addition of preservatives and sucrose. The pulps were blanched, pasteurized and mixed with the preservatives and sucrose according to a complete factorial design with three variables (ratio pulp/sucrose, potassium sorbate and sodium metabisulfite), two levels and two repetitions. The products were filled into high‐density polyethylene packages and exposed to a temperature of 40C for 120 days. Physicochemical, color and chemical (SO₂) analyses showed that the concentrations of sodium metabisulfite and potassium sorbate used did not significantly alter product quality. The addition of sucrose significantly decreased the water activity and led to intense browning. The microbiological evaluations showed good product stability for 120 days. The overall results indicated that the heat treatment applied was effective if high levels of hygiene were maintained during the preparatory stages and the packaging materials were well sanitized. The combined preservation methods appear to be an economic way to preserve these high‐acid pulps.