Search

With increasing consumer awareness of risks associated with a high-fat-intake diet, the market for reduced calorie fats has been expanding. Ten different ratios of ternary blends of palm mid-fraction (PMF), palm stearin (POs) and olive oil (OO) were formulated. The solid fat content of all blends at 37C was in the range of 0.00–24.88%, slip melting points ranged from 0.3 to 53.4C, free fatty acid ranged from 0.14 to 0.34% and iodine value ranged from 35.15 to 87.69%. Fatty acid composition analysis demonstrated that all blends were high in palmitic (12.35–59.95%) and oleic (27.27–71.62%) acids. Higher melting enthalpy was shown by blends with higher degree of saturation. Ternary blends of OO with PMF and POs may be suitable for producing shortening and cocoa butter substitutes with better characteristics than individual oils and fats. Practical Applications To fulfill the increasing demand for low-calorie and healthy foods, many studies have been done with a new oil or fat blend with better nutritional value and reduced calories. Oil blending is a common technique practiced and it is cheaper and involves minimum production of by-products, which are potentially hazardous to health. Blending of palm mid-fraction (PMF), palm stearin (POs) and olive oil was shown to produce an alternative oil source with better physicochemical properties and nutritional value. The ternary oil/fat blend was found to exhibit better oxidative stability and may be suitable as a cocoa butter substitute.

The enzymatic hydrolysis of palm kernel cake protein (PKCP) with trypsin to obtain PKCP hydrolysates (PKCPH) was optimized using response surface methodology (RSM). A central composite design (CCD) was used to study the influence of four independent variables, namely pH, hydrolysis temperature (°C), substrate concentration (w/v) and enzyme/substrate (w/w) ratio on the degree of hydrolysis (DH%). The hydrolysis was carried out using different combinations of four hydrolytic parameters at five levels for 6h. The CCD consisted of 24 experimental points and six replicates of the central points. The data were analyzed using Design-Expert Software. The results showed that all of the variables evaluated significantly influenced the DH% in a second polynomial model, and different combinations of parameters were generated to obtain three different levels of DH (30%, 40% and 50%), namely PKCPH 30, PKCPH 40 and PKCPH 50. The PKCPH with different DH% showed significantly different antiradical properties (p

In this study, the angiotensin I-converting enzyme (ACE) inhibitory peptides were isolated from snakehead fish sarcoplasmic protein hydrolysates. Enzymatic hydrolysis of sarcoplasmic protein was performed using various commercial enzymes. The alcalase hydrolysate with the highest ACE inhibition activity was purified with gel chromatography and reversed phased high-performance liquid chromatography. The purified fractions were then subjected to electrospray ionization quadrupole-micro-time-of-flight mass spectrometry for amino acid characterization. Two novel ACE inhibitory peptides LYPPP and YSMYPP with IC50 values of 1.3 and 2.8 μM were identified, respectively. The pattern of ACE inhibition, resistance to hydrolysis by gastrointestinal proteases and cytotoxic potencies of isolated peptides were described. The results showed no cytotoxicity of peptides on human embryonic fibroblast cell line (MRC-5) and human hepatocarcinoma cell line (HepG2). Practical Applications Freshwater fish muscle proteins and their hydrolysates offer huge potential as novel sources of natural bioactive peptides with angiotensin I-converting enzyme (ACE) inhibitory activity. The present study revealed the identification of two strong ACE inhibitory peptides obtained from alcalase hydrolysis of snakehead fish sarcoplasmic protein. However, further studies are required to determine the in vivo antihypertensive activity of the purified potent ACE inhibitory peptides.

Rambutan anak sekolah (Nephelium lappaceum L.) seed from Malaysia, were analyzed for physicochemical and nutritional composition including proximate composition, mineral contents, solid fat content profiling, triacylglicerol and fatty acid composition. The seeds were abundant in fats (38.9%) and the amount of protein and carbohydrate are 12.4% and 48% respectively. Some chemical properties of seed oil were acid value (0.37%), iodine value (37.64%) and saponification value 157.07. Oleic acid (40.45%) and arachidic acid (36.36%) was the major fatty acid. Triacylglycerol composition of rambutan seed oil was also identified by using HPLC and it shown that AOO (arachidoyl-dioleoylglycerol) was the major compound (49.84%). The Solid fat content profiling of rambutan seed oil shown that it have potential application for food based on fatty product. The mineral elements of seed oil were also involved in this study. The result indicated that rambutan (Nephelium lappaceum L.) seed have a potential as a source of oil or carbohydrate for the human diet and also for food product application.

Protease is one of the most important industrial enzymes with a multitude of applications in both food and non-food sectors. Although most commercial proteases are microbial proteases, the potential of non-conventional protease sources, especially plants, should not be overlooked. In this study, horse mango (Mangifera foetida Lour) fruit, known to produce latex with a blistering effect upon contact with human skin, was chosen as a source of protease, and the effect of the extraction process on its protease activity evaluated. The crude enzyme was extracted from the kernels and extraction was optimized by a response surface methodology (RSM) using a central composite rotatable design (CCRD). The variables studied were pH (x(1)), CaCl(2) (x(2)), Triton X-100 (x(3)), and 1,4-dithryeitol (x(4)). The results obtained indicate that the quadratic model is significant for all the variables tested. Based on the RSM model generated, optimal extraction conditions were obtained at pH 6.0, 8.16 mM CaCl(2), 5.0% Triton X-100, and 10.0 mM DTT, and the estimated response was 95.5% (w/w). Verification test results showed that the difference between the calculated and the experimental protease activity value was only 2%. Based on the t-value, the effects of the variables arranged in ascending order of strength were CaCl(2)pHDTTTriton X-100.

Low-fat bread spreads have become very popular since conventional spreads have been shown to be unhealthy due to high amounts of saturated fat and trans fatty acids. Two interesterified products, sample 16 (4% Thermomyces lanuginosus lipozyme, 4:1 molar ratio of chicken fat to corn oil and 42 h of interesterification at 50oC) and sample 17 (4% lipozyme, 2:1 molar ratio of chicken fat to corn oil and 42 h of interesterification at 30oC), were selected that had the highest Solid Fat Content (SFC) at 30oC. Both the samples contained high proportions of low melting triglycerides, which explains the lower melting temperatures (sample 16, -37.45oC to 31.40oC; sample 17, -39.78oC to 35.4oC) and crystallization temperatures (sample 16, 0.58°C to -38.90oC; sample 17, -2.45oC to -34.27oC for sample 17) and solid fat content (sample 16, 3.2% at 20oC; sample 17, 3.5% at 20oC). The enzymatic process caused the Free Fatty Acid (FFA) values to increase from 0.13-0.48% (sample 16) and 0.16-0.66% (sample 17). The final product (sample 16) had a smaller and less dense fat particle and is a low-cost alternative for soft spreads. The crystallization and melting properties of blends of chicken fat and corn oil result in a product that has a wide plastic range but still contains an unsaturated fatty acid content nearly equal to those based on plan t sources.

Haruan myofibrillar protein was hydrolysed with proteinase K and thermolysin to isolate Angiotensin converting enzyme (ACE) inhibitory peptides. The thermolysin hydrolysate of myofibrillar protein with the highest ACE inhibition activity (IC 50 = 0.033 mg/ml) was fractionated by ultrafiltration and size exclusion chromatography to three fractions. Fraction F2 with higher ACE inhibitory activity was separated into five fractions (A–E) using reversed-phased high performance liquid chromatography (RP-HPLC). Fraction C showed 81% inhibition activity and was subjected to HPLC coupled to electrospray ionisation-time-of-flight mass spectrometry (ESI-TOF MS/MS). Two peptide sequences for the most abundant fragments were identified as VPAAPPK (IC 50 = 0.45 μM) at 791.155 m/z and NGTWFEPP (IC 50 = 0.63 μM) at 1085.841 m/z . The presence of two proline residues at the C-terminal sequence is responsible for the high ACE inhibitory activity of these peptides. The results suggest that Haruan meat protein hydrolysate is a potent ACE inhibitor and may be used to decrease blood pressure.

Turmeric rhizome oleoresin (TRO) was successfully solubilised in aqueous solution by forming inclusion complexes with I²-cyclodextrin (BCD) and I³-cyclodextrin (GCD). To investigate molecular associations of BCD and/or GCD with the oleoresin, phase solubility studies were undertaken, using 1,8-cineole (C10H18O) and ar-tumerone (C15H20O) as marker compounds to represent turmeric oleoresin. In the presence of cyclodextrins, the solubility of 1,8-cineole and ar-tumerone were enhanced. Based on the stability constant, k1:1, the GCD-complex was at least twice effective than BCD. Solid state inclusion complexes were also prepared, using kneading (K) and co-precipitation (CP) methods, and analysed using Fourier transform infrared (FTIR) spectrometry and scanning electron microscopy (SEM). The shift of C{double bond, long}O stretching to higher wavenumbers and strengthening of the C{single bond}O stretching band indicated the formation of a complex between CD and TRO. The new solid phase formed using the co-precipitation method, had a crystal structure which was completely different from the original morphology of oleoresin and cyclodextrins.

Polyphenol components were extracted from Malaysian mix-hybrid cocoa beans from different treatments of fermentation namely; post harvest pod storage, bean spreading and pressing. The polyphenol compounds were analyzed using high pressure liquid chromatography. The (−)-epicatechin, (+)-catechin, theobromine and caffeine of control treatment at 5 days pod storages were 11.87, 4.31, 21.08 and 3.85 mg/g, respectively. Pre-fermentation treatments were found to be significant in affecting the changes in acidity, degree of fermentation and the polyphenol content of cocoa bean. During fermentation, all pre-treated samples showed decreased levels of (−)-epicatechin and (+)-catechin but the rate of decrease were found to be different. It was also found that the (−)-epicatechin and (+)-catechin content before and after fermentation was affected by the type of pre-fermentation treatment used. Percentage lost for (−)-epicatechin and (+)-catechin during fermentation at different degree of fermentation ranged from 6 to 17% and 0.95 to 1.62%, respectively. It was observed that pod storage treatments until 15 days have significant effect in the reduction of acidity, fermentation index (FI) and polyphenol contents compared to spreading and pressing methods. Recoveries (Rv) ranged from 90.90 to 93.92% with % coefficient of variances (CVs) of 6.51, 8.57, 2.42 and 6.37 for (−)-epicatechin, (+)-catechin, theobromine and caffeine, respectively. This study indicates that 15 days pulp preconditioning is the optimum conditions for the degradation of (−)-epicatechin and (+)-catechin, theobromine and caffeine.

In this study, commercial Malaysian cocoa beans (SMC1A) were roasted in a forced airflow-drying oven for 20, 30, 40 and 50 min at 120, 130, 140, 150, 160 and 170C. The products were evaluated for flavor compounds and sensory evaluation (as dark chocolate). The volatile fraction was isolated using the combined steam distillation–extraction procedure and was identified by gas chromatography–mass spectrometry. A quantitative descriptive analysis was used to evaluate the flavor intensity of the chocolates using a 9-point rating scale for selected flavor attributes, namely astringency, bitter taste, sour taste, cocoa and burnt. Panelists were asked to smell and taste the sample against a standard chocolate. It was found that there were significant differences in flavor compounds between the different conditions of roasting. The main flavoring compounds identified composed of aliphatic and alicyclic groups such as alcohol and ester, and heterocyclic groups such as pyrazine and aldehyde. A total of 19 volatile major components were identified: nine pyrazines (2,5-dimethyl-, 2,3-dimethyl-, 2-ethyl-6-methyl-, trimethyl-, 3-ethyl-2,5-dimethyl-, tetramethyl-, 2-ethenyl-6-methyl- and 3,5-dimethyl-2-methylpyrazine); five aldehydes (5-methyl-2-phenyl-2-hexenal, benzaldehyde, benzalacetaldehyde and α-ethyliden-benzenacetaldehyde); one methyl ketone (2-nonanone); two alcohols (linalool and 2-heptanol); and two esters (4-ethylphenyl acetate and 2-phenylethyl acetate). Based on the flavor profile of the compounds identified, an optimum production of the major flavoring compounds such as pyrazine, aldehyde, ketone, alcohol and ester occurred at 160C for 30 min of roasting. Trimethylpyrazine and tetramethylpyrazine compounds together with 5-methyl-2-phenyl-2-hexanal were found to be good indicators for the evaluation of the roasting process. However, based on chocolate evaluation, the best roasting temperature was 150C for 30 min, which gave the lowest astringency and at the same time gave the lowest bitter taste and low level of sour and burnt tastes. At 150C roasting temperature, the desirable cocoa flavor was at its optimum. Correlation coefficients among certain volatile flavor and sensory characteristics of cocoa beans and dark chocolate were significant (P

The changes in physicochemical characteristics of fat blends containing hydrogenated palm kernel oil (HPKO) and goat milk fat (GMF), before and after chemical interesterification using sodium methoxide as catalyst, was evaluated. HPKO : GMF blends were prepared in six ratios: 100:0, 80:20, 60:40, 40:60, 20:80 and 0:100 (w/w). Melting characteristics were studied by differential scanning calorimetry. Peak melting temperatures (Tp) of noninteresterified blends decreased as the percentage of GMF increased. Generally, the interesterified blends showed lower Tpvalues compared to the noninteresterified blends at their respective blending ratios. Decrease in melting enthalpy (Ep) occurred with the increase in percentage GMF in the blends for both the noninteresterified and interesterified blends. Interesterified blends had greater Epvalues than those of the noninteresterified blends at respective ratios. Results from X-ray diffraction analysis showed that all blends possessed a β′ polymorph. HPKO : GMF (0:100) was the only blend in which the presence of both β′ and β polymorphs was detected. Chemical interesterification had no effect on polymorphic crystal behavior. Based on solid fat content (SFC) results, eutectic effect did not occur in all HPKO : GMF blends studied. It was shown that the percentage of SFC decreased as percentage of GMF increased. Decrease in percentage SFC of blends was brought about by interesterification. The HPKO : GMF (100:0) blend had the highest percentage of free fatty acid followed by HPKO : GMF (0:100). Interesterification caused a 2- to 3-fold increase in the percentage of free fatty acids compared to noninteresterified blends. Iodine values of the blends increased with an increase in GMF proportion. A rapid increase in iodine was observed in blends containing 0–20% GMF. Interesterification did not have any effect on the iodine value of fat blends.

The objectives of this research were to improve the low-temperature performance of palm oil products, with emphasis on non-food uses, and to find some additives (synthesized or commercially available) suitable to reduce the pour point and cloud point values of palm oil products. The samples studied in this research include palm olein (PO), super olein (SO), palm oil methyl esters (POME), palm kernel oil methyl esters (PKOME), a blend of POME and PO at a 2:1 ratio (POMEPO), a blend of POME and SO at a 2:1 ratio (POMESO), a blend of PKOME and PO at a 2:1 ratio (PKOMEPO) and a blend of PKOME and SO at a 2:1 ratio (PKOMESO). Among the additives studied in this research were Tween-80, dihydroxy fatty acid (DHFA), acrylated polyester pre-polymer, palm-based polyol (PP), a blend of DHFA and PP at a 1:1 ratio (DHFAPP), an additive synthesized using DHFA and ethyl hexanol (DHFAEH), and castor oil ricinoleate. All the additives used showed satisfactory results, with more significant reductions of pour point and cloud point values observed for POME, PKOME, POMEPO, POMESO and PKOMESO samples. The biggest reduction of the pour point value in this research was about 7.5 °C (by addition of 1.0% DHFA to POMEPO), while the biggest reduction of the cloud point value was about 10.5 °C (by addition of 1.0% DHFA + 1.0% PP to POME). The significant reductions in pour point and cloud point values of POME, PKOME, POMEPO, POMESO and PKOMESO by the additives used indicate that the additives might be able to improve the low-temperature properties of palm oil products, for instance biodiesel.

This research was carried out to determine the effect of fractionation temperature on the physicochemical characteristics of refined, bleached and deodorized (RBD) palm oil and sunflower oil blends fractionated at different temperatures. Blends of 20% and 40% sunflower oil with 80% and 60% RBD palm oil, respectively, were fractionated at three different temperatures (15, 18 and 21 °C). The results showed that olein with higher iodine value was obtained at lower fractionation temperature. This was because, at lower fractionation temperature, more of the polyunsaturated fatty acid, namely linoleic acid (C18:2), went into the liquid fraction. On the other hand, more of the saturated fatty acid, namely palmitic acid (C16:0), went into the liquid fraction at higher fractionation temperature. Blending reduced the triacylglycerol composition, namely POP, POS, SOO and PLP, while OLO, PLL, OLL and LLL/LLnO increased. Lower fractionation temperature decreased the composition of monosaturated triacylglycerol and increased the composition of di- and polyunsaturated triacylglycerols. Lower fractionation temperature produced a liquid fraction with lower solid fat content and lower cloud point than did higher fractionation temperature.

A cyclodextrin glucanotransferase (CGTase) was successively purified by ammonium sulphate precipitation, and affinity chromatography on α-CD (epoxy)-Sepharose 6B column. The specific activity of the CGTase was increased approximately 2200-fold, from 8.43 U/mg protein to 18,866 U/mg protein. SDS-PAGE showed that the purified CGTase was homogeneous and the molecular weight of the purified CGTase was about 75 kDa. The molecular weight of the enzyme that was estimated by gel filtration under native condition was 79 kDa. This has indicated that Bacillus sp. G1 CGTase is a monomeric protein. The isoelectric point (p I ) of the enzyme was about 8.8. Characterization of the enzyme exhibited optimum pH and temperature of 6.0 and 60 °C, respectively. The enzyme was stable from pH 7.0 to 9.0 and retained its high activity up to 60 °C. However, in the presence of 20 mM Ca 2+ , the purified CGTase is able to prolong its thermal stability up to 70 °C. CGTase was strongly inhibited by ZnSO 4 , CuSO 4 , CoCl 2 , FeSO 4 , FeCl 3 and EDTA. K m and V max for the purified enzyme were 0.15 mg/ml and 60.39 mg β-cyclodextrin/(ml min), respectively, with soluble starch as substrate. In cyclodextrin production, tapioca starch was found to be the best substrate used to produce CDs. The enzyme produced γ- and β-CD in the ratio of 0.11:0.89 after 24 h incubation at 60 °C, without the presence of any selective agents.

Summary Antioxidant activities of myofibrillar protein hydrolysates (MPH) prepared from patin (Pangasius sutchi) using papain and Alcalase® 2.4 L with different degrees of hydrolysis (DH) were investigated. With a DH of 65.83%, the hydrolysate prepared with papain exhibited the maximum of 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical-scavenging activity (71.14%) with a reducing power of 0.310. At a concentration of 1 mg mL−1, the papain-MPH exhibited a Trolox equivalent antioxidant capacity (TEAC) of 70.50 ± 1.22 μmol g−1 protein. With a DH of 83.6%, the Alcalase-MPH had the highest metal-chelating activity. Low molecular weight peptides showed higher antioxidant activities than high molecular weight peptides. Both papain-MPH and Alcalase-MPH contained high amounts of the essential amino acids (48.71% and 48.10%, respectively) with glutamic acid, aspartic acid and lysine as the dominant amino acids. These results suggest that the protein hydrolysates derived from patin may be used as an antioxidative ingredient in both functional food and nutraceutical applications.

The Cr(III) sorption experiments onto Kappaphycus alvarezii waste biomass were conducted at different pH values (2–6) under the conditions of initial metal concentration of 10–50 mg/L and the chemical compositions of Cr-Cu and Cr-Cd. The Cr(III) sorption capacities were slightly dependent on pH, and the maximum sorption capacity was 0.86 mg/g at pH 3. The sorption capacities increased with increase in the initial metal concentration, whereas it was suppressed by the presence of Cu(II) and Cd(III) in the solution. The Cr(III) sorption equilibrium was evaluated using Langmuir, Freundlich and BET isotherms. The sorption mechanisms were characterised using scanning electron microscopy and Fourier transform infrared spectroscopy. The main mechanisms were ion exchange coupled with a complexation mechanism. Kappaphycus alvarezii waste biomass represents a potential for Cr(III) ion removal from aqueous solution.

This study was conducted to evaluate the kinetic characteristics of proteolytic activity of proteases on Channa striatus protein fractions. Degree of hydrolysis (DH), amino acid composition and kinetic parameters of sarcoplasmic and myofibrillar proteins were investigated when incubated with proteinase K and thermolysin, separately. After 30 min incubation with proteases, a decrease in DH of sarcoplasmic protein was observed whereas, hydrolysis of myofibrillar protein with proteases took 2 h with an increase in DH. The major amino acids were glutamic acid (16.6%) in thermolysin- myofibrillar hydrolysate followed by aspartic acid (11.1%) in sarcoplasmic protein fraction with no enzyme treatment and lysine (10%) in thermolysin-myofibrillar hydrolysate. The apparent Michaelis constant of proteinase K was lower than thermolysin for both sarcoplasmic and myofibrillar proteins. However, rate of turnover and enzyme efficiency suggested that sarcoplasmic and myofibrillar proteins are suitable substrates for proteinase K and thermolysin hydrolytic reaction, respectively.

In Malaysia bean spreading was investigated as an alternative method to pod storage for preconditioning of pulp in order to reduce nib acidification during subsequent cocoa fermentation. Harvested pods were broken and the seeds were exposed to quick pulp surface drying either by spreading in full sunshine or by the use of a suitable drier. A decrease in the volume, water and sugar content was observed during spreading, which caused subsequent shallow box fermentation to run similarly to stored pod fermentation, showing a steep temperature increase, absence of an initial anaerobic phase, reduced acetic acid formation and a higher minimum pH value in the nibs. Irregularities in fermentations and practical problems are discussed.

Patchouli essential oil can be obtained from fresh, dried and fermented plant material. It is a highly valuable product in the fragrance industry and its quality changes depending upon raw material age and oil storage. In this work, patchouli essential oils derived from different treatments have been subjected to GC-FID quantitative analysis using an internal standard (ISTD) method with response factors (RF). Samples were obtained from i) fresh plants; ii) hydrodistillation of one year mature and fermented plants; iii) hydrodistillation of one year mature plants; iv) commercial products from Indonesia and Malaysia. Linear Retention Indices (LRI) for both polar and non-polar GC-MS analyses were also measured as a tool for qualitative analysis towards a homologous series of C7-C30 n-alkanes. The results obtained confirmed that, in all samples, patchouli alcohol was the main volatile constituent, with higher amount in lab-scale produced oils, compared with commercial samples. Other major compounds, in lab oils and commercial samples respectively, were: δ-guaiene, α-guaiene, pogostol, seychellene and α-patchoulene. Another 36 compounds were also found.

Preparation of a single and pure phospholipid via transphosphatidylation has been a much sought after endeavor in the pharmaceutical and nonmedical industries. For this reason, phosphatidylglycerol, a lung surfactant, was produced from phosphatidylcholine with defined fatty acids, ie, dipalmitoyl phosphatidylcholine. Substrate type and concentration, enzyme source, and reaction temperature were investigated. Phospholipase D from two sources, ie, savoy cabbage, was purified in the authors’ laboratory and a commercially available Streptomyces species was used for this study. The substrates used were glycerol, a polyhydric alcohol, and solketal, a monohydric form of glycerol. The progress of the reaction was monitored using thin layer chromatography, and synthesis with solketal, an unusual form of glycerol, was confirmed by liquid chromatography mass spectrometry. Surface response methodology used on four combinations of enzyme and substrate at various temperatures (30 °C–60 °C) and concentration (0.25–1 mM) revealed that yield and selectivity was temperature-driven and predictable. To validate further the thermodynamic attributes, a modified version of the Eyring equation was derived from selectivity and the Arhenius equation. These equations provide some useful insights into the difference in activation of enthalpy change(ΔΔH++) and difference in activation of entropy change(ΔΔS++). Plots of ln[PG]/[PA] versus 1/T gave good linear fits for these four combinations. In addition, a new thermodynamic parameter known as TPG = PAhas emerged as a theoretical temperature for equivalent transferase and hydrolase activity.

Results from the present study have shown that the ionic species of buffers, pH values and reaction temperature can affect the enzyme unit activities and product specificity of Toruzyme (Novo Nordisk A/S Bagsvaerd, Denmark) CGTase (cyclodextrin glucanotransferase). Applying a similar reaction environment (acetate buffer, pH 6.0; temperature, 60 degrees C), the CGTase was found to be capable of producing pre dominantly beta-cyclodextrin from either raw or gelatinized sago (Cycas revoluta) starch. Changing the buffer from acetate to phosphate reduced the yield of beta-cyclodextrin from 2.48 to 1.42 mg/ml and also affected the product specificity, where production of both alpha- and beta-cyclodextrins were more pronounced. The decrease in the production of cyclodextrins in phosphate buffer was significant at both pH 6.0 and 7.0. However, changing the buffer to Tris/HCl (pH 7.0) showed a significant increase in beta-cyclodextrin production. Increasing the ionic strength of sodium acetate and Tris/HCl buffers at pH 6.0 and 7.0 to equivalent ionic strength of phosphate buffers showed no significant effects on cyclodextrin production. Higher yield of cyclodextrins at pH 7.0 when Tris/HCl was used might be due to the binding of chloride ions at the calcium-binding sites of the CGTase, resulting in the shift of the optimum pH close to physiological environment, leading to an increase in the activities and specificity.

In Malaysia, pulp preconditioning by post-harvest storage of cocoa pods leads to the reduction of nib acidification during subsequent fermentation, reduction of the acid note and an increase in cocoa flavour in the resulting raw cocoa. Data from several shallow-box fermentations, with material from unstored and stored pods, are compared and interpreted, obtained in the years 1984 to 1987 in a cooperational investigation of the Malaysian Agricultural Research and Development Institute (MARDI), Malaysia, and the Botanical Institute, Technical University of Braunschweig (TUBS), FRG. Prior to and during fermentation, pulp volume and pulp sugars; pH value, acetic acid and lactic acid content in the pulp and nibs; and oxygen concentration and temperature in the mass were determined. Some flavour assessments from selected samples are given. The great reduction in pulp volume per seed rather than the decrease of pulp sugars per seed during pod storage was found to be of the most importance. Pulp-volume reduction enhances mass aeration and increases the ratio of respiration to ethanol fermentation and its subsequent oxidation to acetic acid. As a consequence, the acidification of the seeds during the formative stages of flavour precursors (after the death of the seeds) is strongly reduced. With effectively dry stored pods (pulp volume per gram of seed ≤0·6 ml) the anaerobic phase during the initial stages of fermentation which is common with unstored pods is suppressed. Under these conditions the nib pH value does not fall below 5·0 and no drastic acid (and flavour) degradation at the end of fermentation is necessary to reduce the acidity in the seeds.

Changes in the pulp during ripening and post-harvest storage of cocoa pods were determined during numerous harvests in Malaysia (1984 to 1987) and Ghana (1985 to 1986), in order to gain a basis for understanding the influence of ripening and storage on acid formation during subsequent fermentation. Changes in the pulp during ripening of fully grown pods were the same but less pronounced than those during dry storage of harvested pods: the percentage of water in the pulp was not changed significantly, but the amount of water and of dry matter per seed was strongly reduced (by 40–50%) due to water evaporation and respiration of sugars. Sucrose was inverted completely. The result of these changes was an equally strong reduction of the pulp volume per seed and increase of the pulp surface to pulp volume ratio. The reduction of acid formation during fermentation with beans from stored pods is ascribed predominantly to these changes rather than to the reduction in the amount of sugars, and is explained not only by the facilitated mass aeration but, above all, by the significant increase in respiration at the pulp surface over ethanol fermentation in the pulp when the pulp volume is reduced prior to fermentation. Ghanaian pods at similar stages of ripeness revealed more advanced stages of the pulp compared with Malaysian pods and consequently less significant change during storage. Water evaporation and respiration during pod storage were significantly higher in the pulp than in the husk.