Effect of high hydrostatic pressure on starches: A review

Various strategies have been employed to enhance starch property, including thermal processing, chemical modification. The application of high hydrostatic pressure (HHP) may be a complementary, synergistic, or an additive starch enhancement technique. While most current applications of HHP are in starch processing, over 25 starches had been investigated by HHP, which can induce gelatinization and modification of some starches. Different starch responds differently to high pressure depending on the pressure range, starch source, pressurization temperature and time, different solvent and starch concentration. We have re‐examined the information on the various factors that influence the HHP‐induced structure, gelatinization, retrogradation, and modification of starches from different plant sources, with an emphasis on the HHP‐induced gelatinization. The compiled evidence of high pressure starch enhancement in this paper indicates that HHP is an effective technology with potential for greater utilization in starch application.     

Inactivation kinetics of three Listeria monocytogenes strains under high hydrostatic pressure

High hydrostatic pressure (HHP) inactivation of three Listeria monocytogenes strains (EGDe, LO28, and Scott A) subjected to 350 MPa at 20 degrees C in ACES buffer resulted in survival curves with significant tailing for all three strains. A biphasic linear model could be fitted to the inactivation data, indicating the presence of an HHP-sensitive and an HHP-resistant fraction, which both showed inactivation according to first-order kinetics. Inactivation parameters of these subpopulations of the three strains were quantified in detail. EGDe showed the highest D-values for the sensitive and resistant fraction, whereas LO28 and Scott A showed lower HHP resistance for both fractions. Survivors isolated from the tail of LO28 and EGDe were analyzed, and it was revealed that the higher resistance of LO28 was a stable feature for 24% (24 of 102) of the resistant fraction. These HHP-resistant variants were 10 to 600,000 times more resistant than wild type when exposed to 350 MPa at 20 degrees C for 20 min. Contrary to these results, no stable HHP-resistant isolates were found for EGDe (0 of 102). The possible effect of HHP survival capacity of stress-resistant genotypic and phenotypic variants of L. monocytogenes on the safety of HHP-processed foods is discussed.     

超高压辅助制备醋酸酯淀粉结构性质研究

以玉米淀粉为原料,乙酸酐为反应试剂,NaCl为反应介质,采用超高压辅助制备醋酸酯淀粉,利用光学显微、X-射线衍射、快速黏度分析技术对醋酸酯淀粉结构性质进行分析。研究表明,颗粒态醋酸酯淀粉结晶类型与原淀粉相同,当处理压力为600 MPa时淀粉糊化,颗粒结构被破坏,A型结晶向V型结晶转换,但糊化并不利于醋酸酯淀粉取代度的增加。适量NaCl的添加有利于超高压处理时淀粉颗粒态的维持,因而有效提高了醋酸酯淀粉的取代度。当NaCl溶液浓度为1.0%、乙酸酐添加量为2.0%、压力为400MPa时,所制备的醋酸酯淀粉取代度达到最大值(0.090),且表现出较高的峰值黏度(400.00cP)。     

Some characteristics of acetylated, cross-linked and dual modified Indian rice starches

Starches from broken rice grains derived from three varieties (PUSA-44, PR-106, and PR-114) were modified by hydroxypropylation with propylene oxide and esterification with adipic acid anhydride and/or vinyl acetate. Degree of substitution and acetyl contents (in parentheses) was relatively low; ranges between 0.02 (0.53%) and 0.12 (3.09%) for hydroxy-propylated cross-linked and acetylated starch samples. The acetylation and dual modification of starches increased the paste clarity, solubility, swelling power, sediment volume, and gel strength but decreased the gel elasticity in all the three varieties. However, the adhesiveness increased only upon dual modification in PUSA-44 and decreased in other two varieties. Cross-linking reduced the solubility, swelling power, sediment volume, and gel elasticity while increased the paste clarity, gel strength and adhesiveness. The physico-chemical characteristics of relatively high amylose variety PUSA-44 among three varieties were significantly lower than those from varieties with low amylose content whereas PUSA-44 had shown improved gel properties as compared to other two varieties.     

Retrogradation kinetics of chestnut starches cultivated in three regions of Korea

Retrogradation kinetics of chestnut starches from three different regions of Korea were investigated during storage at 4 °C. The retrogradation properties were determined using four DSC characteristics: glass transition temperature (\( {\text{T}}_{\text{g}}^{\prime } \)), ice melting enthalpy (ΔH_i), amylopectin melting enthalpy (?H_r) and degree of retrogradation (DR). The Gongju (GJ) starch showed the highest gelatinization enthalpy (?H_g) value, followed by Gwangyang (GY) and Hadong (HD). \( {\text{T}}_{\text{g}}^{\prime } \) of all samples gradually increased with increasing storage time, while ?H_i decreased as the storage time increased. ?H_r of all samples significantly increased after 2 days of storage. DR, calculated based on ?H_g and ?H_r, showed a similar tendency with ?H_r. The retrogradation rates of three chestnut starches were analyzed using the Avrami equation, and the time constants (1/k) were obtained. GY, GJ and HD showed the fastest retrogradation rate in \( {\text{T}}_{\text{g}}^{\prime } \), ?H_i, and ?H_r, respectively suggesting that each sample experienced different retrogradation kinetics in different region.     

Retrogradation properties of rice starch gelatinized by heat and high hydrostatic pressure (HHP)

Retrogradation process of pressure-gelatinized rice starches was investigated and compared with the heat-gelatinized ones in this study. Our results showed that the retrogradation rate of normal rice starch gelatinized by high hydrostatic pressure (HHP) was slower than that by heat. Nevertheless, there was no difference in retrogradation rate for waxy rice starch gelatinized by the two treatments (P > 0.05). The DSC data were further analyzed using the Avrami equation. The result indicated that the pressure-gelatinized normal rice starch had a lower recrystallization rate (k) and a higher Avrami exponent (n) than the heat-gelatinized one, but the two treatments did not affect the k and n for waxy rice starch. Furthermore, the intact starch granules and lower amylose leaching were observed only in the pressure-gelatinized normal rice starch. These findings suggest that the retardation mechanism of HHP on starch retrogradation is probably attributed to less broken granules and lower leached amylose.     

交联氧化乙酰化蜡质玉米淀粉性质的研究

以蜡质玉米淀粉为原料、三偏磷酸钠为交联剂、次氯酸钠为氧化剂、醋酸酐为乙酰化试剂,采用湿法工艺制备交联氧化乙酰化复合变性淀粉,并利用扫描电镜(SEM)及红外光谱仪(FT-IR)分析其淀粉颗粒的形貌及结构。结果显示:复合变性处理后的淀粉白度升高至97.2,糊透光率升高至71.0%,耐酸及抗剪切性能也有所改善。扫描电镜图表现了淀粉颗粒形貌的变化,红外光谱图中展现的各基团的特征吸收峰表明其分子结构发生了改变。蜡质玉米淀粉采用复合变性的处理手段,有益于增强其在食品加工领域的应用价值。     

Characterization of amorphous granular starches prepared by high hydrostatic pressure (HHP)

Amorphous granular starches (AGS) and non-granular amorphous starches (non-AGS) of corn, tapioca and rice were prepared using high hydrostatic pressure (HHP) treatment with ethanol and water washing, respectively and their physicochemical properties were investigated. Water holding capacity and apparent viscosity of AGS and non-AGS were higher than those of native one in all starches. In RVA pasting properties, AGS and non-AGS showed higher pasting temperature and lower peak viscosity than those of native one. Furthermore, non-AGS showed distinctively lower peak viscosity compared to that of AGS possibly due to its non-granular structure. Apparent viscosity of non-AGS revealed relatively lower than commercial pre-gelatinized starch because of heat and pressure-induced gelatinization. Maintaining granular structure in HHP treated pre-gelatinized starch provide a distinctive physicochemical characteristics compared to native starch and preparation of gelatinized starch with different gelatinization and washing methods could cause big differences in their physicochemical properties.     

Anthocyanin condensation reactions under high hydrostatic pressure

The effects of temperature and/or high hydrostatic pressure on anthocyanin condensation reactions were studied. For this purpose, model solutions containing cyanidin-3-O-glucoside (Cy3gl) and pyruvate, in excess, were subjected to different combined temperature/pressure treatments. After a high hydrostatic pressure treatment of 600 MPa, at 70 °C during 30 min, about 25% of Cy3gl was degraded. Parallel to this decrease, a vitisin A-type derivative was formed. By contrast, the rate of condensation was only 5% when samples were heated (70 °C, 30 min). In both cases, the degradation kinetics fitted well to a first order reaction (R² = 0.99). The decrease in Cy3gl was correlated with a decrease in the antioxidant activity. Moreover, the chemical stability of wine subjected to a temperature/pressure treatment of 600 MPa, at 70 °C during 1 h was investigated. After this treatment, a decrease in the concentration of malvidin-3-O-glucoside (Mv3glu) was found. As a consequence, an increase in the concentration of several products of high molecular weight at 370 nm was observed. When wine was subjected to pasteurization conditions (600 MPa, 70 °C, 10 min), no significant changes in the chemical composition were found (P < 0.05).     

Behaviour of partially cross-linked casein micelles under high pressure

High pressure (HP) treatment of a casein micelle suspension at 250 and 300 MPa leads to an initial rapid increase of its light transmission, as measured in situ , indicating micellar disruption. Subsequently, a much slower, partial reversal of the HP-induced increase in light transmission is observed, indicating re-association of micellar fragments. Partial internal cross-linking of the casein micelles by the enzyme transglutaminase prior to pressure treatment slows down both the disruption and the reassociation process considerably. It is proposed that covalent cross-linking provides the micelle with extra stability against pressure-induced disruption and also prevents a molecular reorganization process required to induce reassociation of micellar fragments during prolonged pressure treatment.     

Maillard-type reactions under high hydrostatic pressure: Formation of pentosidine

Application of hydrostatic pressure up to 600 MPa on a solution consisting of N ^α -acetylarginine, N ^α -acetyllysine and ribose in equimolar ratios (pH 7.4, T=60 °C, t=2 h) resulted in a pressure-dependent increase of the pentosidine content. This marker for the advanced Maillard reaction could also be found protein-bound in enhanced yields by increasing pressure on β-casein incubated with ribose in solution. Received: 4 January 2000     

Phase transition of cross-linked and hydroxypropylated corn (Zea mays L.) starches

The thermal behaviors of three chemically modified starches (cross-linked waxy corn, hydroxypropylated regular corn, and hydroxypropylated and oxidized waxy corn) were studied using light microscopy, SEM, DSC, XRD, and HPSEC. During the gelatinization process, molecular and crystalline order losses occurred independently from each other. Oxidation treatment altered the effects of hydroxypropylation on starch gelatinization. Both cross-linking and hydroxypropylation tended to preserve granular crystalline order during initial stages of gelatinization. The crystallinities and X-ray patterns of each starch remained essentially unchanged prior to phase transition.     

Effect of high hydrostatic pressure on modified noncrystalline granular starch of starches with different granular type and amylase content

Waxy corn (A-type pattern, amylopectin with trace amounts of amylase) and tapioca starch (C-type pattern, 17 g/100 g amylase content) were modified by High Hydrostatic Pressure (HHP) to produce noncrystalline granular (NCG) starch, respectively. The changes in the starch structure and properties occurring upon modified NCG after high-pressure treatment (300–600 MPa/30 min) were analyzed using polarized light microscopy (LM), differential scanning calorimetry (DSC), particle size distribution and scanning electronic microscopy (SEM). The resulting modified NCG starch took place when the 50 g/100 g starch suspension was treated under 450 MPa for the waxy corn starch with swelling degree of 57.07%, whereas 600 MPa for the tapioca starch with restricted starch swelling degree of 16.48%, indicating the stabilization effect of amylase. Also, they had reduced gelatinization temperatures, and lower pasting viscosities, which suggested that HHP had an effect on the physicochemical properties of native starch by destabilization, hydration and swelling.     

Infusion efficiency of fluorescein derivatives of different molecular sizes into various starches under atmospheric and high hydrostatic pressures

Food Science and Biotechnology - Fluorescein isothiocyanate-dextrans (FDs) of different molecular weights were infused into corn, waxy rice, tapioca, and potato starches under atmospheric and high...     

Comparison of bactericidal activity of six lysozymes at atmospheric pressure and under high hydrostatic pressure

The antibacterial working range of six lysozymes was tested under ambient and high pressure, on a panel of five gram-positive (Enterococcus faecalis, Bacillus subtilis, Listeria innocua, Staphylococcus aureus and Micrococcus lysodeikticus) and five gram-negative bacteria (Yersinia enterocolitica, Shigella flexneri, Escherichia coli O157:H7, Pseudomonas aeruginosa and Salmonella typhimurium). The lysozymes included two that are commercially available (hen egg white lysozyme or HEWL, and mutanolysin from Streptomyces globisporus or M1L), and four that were chromatographically purified (bacteriophage lambda lysozyme or LaL, bacteriophage T4 lysozyme or T4L, goose egg white lysozyme or GEWL, and cauliflower lysozyme or CFL). T4L, LaL and GEWL were highly pure as evaluated by silver staining of SDS-PAGE gels and zymogram analysis while CFL was only partially pure. At ambient pressure each gram-positive test organism displayed a specific pattern of sensitivity to the six lysozymes, but none of the gram-negative bacteria was sensitive to any of the lysozymes. High pressure treatment (130-300 MPa, 25 degrees C, 15 min) sensitised several gram-positive and gram-negative bacteria for one or more lysozymes. M. lysodeikticus and P. aeruginosa became sensitive to all lysozymes under high pressure, S. typhimurium remained completely insensitive to all lysozymes, and the other bacteria showed sensitisation to some of the lysozymes. The possible applications of the different lysozymes as biopreservatives, and the possible reasons for the observed differences in bactericidal specificity are discussed.     

Gelatinization of waxy starches under high pressure as influenced by pH and osmolarity: Gelatinization kinetics, final structure and pasting properties

We investigated the influence of pH and osmolarity on the high-pressure-induced gelatinization of waxy corn and waxy rice starches in salt solutions, and the properties of the resulting gels. Gelatinization kinetics, the gel swelling power of starches, their structure and their rheological properties were studied for starch suspensions treated at 500 MPa. Gelatinization took place mostly in the first 15 min of the pressure treatment and both the gelatinization speed and the maximal level of gelatinized starch decreased with increasing osmolarity. pH had a minor influence on gelatinization kinetics differing from one starch to another. The resulting gels appeared as a mix of a gel and starch granules with a higher proportion of native granules with increasing osmolarity. Gel strength and swelling were positively correlated to their proportion of gelatinized starch. Thus, gels with different structures and gelatinization levels can be obtained under pressure depending on pH and osmolarity.     

超高压对双孢蘑菇的杀菌效果和动力学的研究

以细菌总数、大肠菌群、酵母菌和霉菌数为对象,研究了超高压(High hydrostatic pressure,HHP)处理对双孢蘑菇(Agaricus bisporus)的杀菌效果和杀菌动力学。双孢蘑菇在300、400、500、600MPa压力下,室温下分别用HHP处理2.5～25min。结果表明:随压力的升高和时间的延长,杀菌效果增强;霉菌、酵母对压力较为敏感,400MPa处理2.5min可将其全部杀死;300MPa处理2.5min可完全杀灭双孢蘑菇中的大肠菌群。应用Weibull模型对不同处理条件下双孢蘑菇的杀菌效果进行拟合,拟合动力学曲线的决定系数R2均大于0.97,拟合效果较好。提出了双孢蘑菇的HHP杀菌的最优杀菌工艺参数,即600MPa处理5min,该条件即可以有效杀灭双孢蘑菇中的微生物。